Indian Patents. 216747:A PERSON FOR THE SYNTHESIS OF REACTIVE POLYMERS AND COPOLYMERS FROM VINYLBENZYL METHACRYLATE

Title of Invention	A PERSON FOR THE SYNTHESIS OF REACTIVE POLYMERS AND COPOLYMERS FROM VINYLBENZYL METHACRYLATE
Abstract	The present invention provides a process for the production of reactive polymers and copolymers from p-vinylbenzylmethacrylate with pendent double bonds exhibiting narrow molecular weight distribution using anionic initiator.

Full Text	This invention relates to a process for the synthesis of reactive polymers and copolymers from vinylbenzylmethacrylate. More particularly the present invention relates to a process for the production of reactive polymers and copolymers from p-vinylbenzylmethacrylate with pendent double bonds exhibiting narrow molecular weight distribution using anionic initiator. Bi-functional monomers having two polymerizable groups are of great interest to polymer chemists. The well-known divinyl monomers are divinylbenzene (1,3- and 1,4- isomers), diisopropenylbenzene (1,3- and 1,4- isomers), ethylenegylcoldimethacrylate, allylmethacrylate, 2-(acryloxy)ethyl methacrylate and p-vinylbenzylmethacrylate. These difunctional monomers are generally used '-polymerization to induce cross-linking (CA 129:140709, EP: 98-100634 (1998) and JP: 95-233771 (1995)). Synthesizing linear polymer from difunctional monomers with one vinyl group intact in every repeating unit is possible in some cases using anionic polymerization (Makromol. Chem. 183, 2787, 1982; Macromolecules, 29, 1753, 1996). Polymers having polymerizable functional groups at each repeat unit or at its portion of chain segment can be used as reactive polymers in many applications such as cross-linking agent in extruder, controlled post grafting, thermal cross-linking agent in the production of high refractive-index transparent organic glass (JP: 06116336 A2, 1994) and various other polymer composite formulations. Although the reactivity of the two vinyl groups in difunctional monomers differ to certain extent, the initiation source used in many polymerization techniques are more reactive compared to propagating species and does not allow selective initiation of one vinyl group. However, Group Transfer polymerization (GTP) enables the use of silyl Ketene acetals with a suitable catalyst to initiate only polar vinyl monomer such as alkyl (math)acrylate (J. Am. Chem. Soc., 105, 5706, 1983). Attempts to polymerize p-vinylbenzylmethacrylate through its methacrylate double bond using GTP resulted in low conversions (40 to 81 %) and the polymer exhibited broad molecular weight distribution (MJMn = 8.3) (Polym. Bull.,14, 105, 1985). This indicates that an exclusive polymerization of one vinyl group is not possible by GTP. Linear polymerization of 1,3-diisopropenylbenzene using an anionic initiator in THF at low temperature has been demonstrated (Makromol. Chem., 183, 2787, 1982). It is known that the reactivity of the two vinyl groups in p-vinylbenzylmethacrylate is widely different. Anionic polymerization of styrene requires a strong initiator like alkyllithium where as a less reactive initiator such as 1,1-diphenylhexyllithium is sufficient to provide a controlled initiation foi methacrylate monomers. The reactivity difference of methacrylic and stryrenic double bonds in p-vinylbenzylmethacrylate provides a means of polymerizing p-vinylbenzylmethacrylate using DPHLi as initiator through its methacrylate group without affecting the styrene group. The main object of the present invention is, therefore, to provide a process for the synthesis of reactive polymers and copolymers from /?-vinylbenzylmethacrylate, which obviates the drawbacks as detailed above. Another object is to produce star polymers by post cross-linking of the pendent double bonds of the short blocks of di-block copolymers such as poly (methvlmethacrylate-^-vinylbenzylmethacrylate), poly (styrene-£-vinylbenzyl methacrylate), poly (butadine-fe-vinylbenzylmethacrylate), and poly (isoprene-fc-vinylbenzyl methacrylate) using free radical initiators. Still another object is to enable the production of grafted-network copolymers by polymerizing di-btock copolymer consisting of short-chain, pendent double bonds with any other comonomers using a free radical initiator. Accordingly, the present invention provides a process for the synthesis of reactive polymers and copolymers for p-vinylbenzylmethacrylate which comprises preparing a mixture of organolithium initiator-additive solution such as herein described, wherein the mole ratio of organolithium initiator to additive ranging from 1 : 1 to 1 : 40?cooling the said mixture to -78°C + 10°C, adding p-vinylbenzylmethacrylate to the organolithium initiator - additive solution under stirring, to obtain a solution of reactive poly (p- vinylbenzylmethacrylate), adding a second monomer selected from the group comprising styrene, alpha-methylstyrene, butadiene, isoprene, alkyl (meth) acrylate such as methyl methacrylate, ethyl methacrylate, n or f-butyl methacrylate, lauryl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and t-butyl acrylate to get a reactive di-block copolymer consisting of p-vinylbenzylmethacrylate segments, terminating the polymerization with degassed methanol and separating the polymer/ co-polymer by conventional precipitation using a non-solvent. In an embodiment of the present invention, the organolithium initiator used may be prepared by reacting one mole of n-, secondary, or tertiary-butyllithum with 1,1-diphenylethylene or a- methylstyrene or by direct metalation of methyl or ethyl isobutyrate using lithium diisopropylamide, triphenylmethane by potassium in tetrahydrofuran (THF). In another embodiment, the additive used may be such as the salt of an alkaline or alkaline-earth metals of acids such as lithium chloride, lithium perchlorate, the salt of an alkaline and alkaline-earth metals of mono-, di-, tri- and tetraethylene glycols or monoalkoxyglycols which can be prepared by reacting with metallic lithium or by the reaction with an organometallic lithium compound in polar or apolar solvent. In an another embodiment, the solvent used for preparing solution of initiator-additive may be selected from tetrahydrofuran (THF), tetrahydropyran (THP), aromatic hydrocarbon or a mixture of aromatic hydrocarbon and tetrahydrofuran. In yet another embodiment, the lowest volume % of THF in the mixture is above 5 % (v/v), preferably 10%. In still another embodiment, the aromatic hydrocarbon may be selected amongst benzene, toluene, xylene, ethylbenzene, mesitylene and tetralin preferably toluene. In still another embodiment, the mole ratio of organolithium initiator to additive can vary from 1:1 to 1:40 preferably 1:10. In still another embodiment, the concentration of organolithium initiator may be between 0.3 to 2 millimole/litre and the concentration of p-vinylbenzylmethacrylate is in the range of 0.1 to 0.4 mole/litre. In another embodiment, the comonomer optionally may be styrene, a-methylstyrene, butadiene, isoprene, alkyl (meth) acrylate such as methyl methacrylate, ethyl methacrylate, n or ?-butyl methacrylate, lauryl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and r-butyl acrylate. The process of the present invention is described herein below with examples, which are illustrative only and should not be construed to limit the scope of the invention. Example 1 Anionic polymerization of p-vinylbenzylmethacrylate, using 1,1-diphenylhexyllithium (DPHLi) in presence of lithium perchlorate in tetrahydrofuran at -78 °C Into a dry 250 mL round bottom flask equipped with magnetic needle, nitrogen/vacuum three-way adapter with rubber septum, was added 100 mL of dry tetrahydrofuran. A tetrahydrofuran solution (2 mL) containing 0.200 grams of lithium perchlorate was added and the reaction flask was cooled to -78 °C. A tetrahydrofuran solution of 1,1-diphenylhexyllithium (DPHLi) was added drop wise under stirring until the initiator color persisted. Then, 1.4 mL (1.3 x 10"4 moles) of DPHLi (0.093 M) in tetrahydrofuran was added. After few minutes, 2.4 mL (0.012 moles) of purified p-vinylbenzylmethacrylate (freshly distilled from calcium hydrate) was transferred by stainless steel capillary under stirring using pure nitrogen pressure and the polymerization continued for 15 min. The reaction was terminated by adding degassed methanol. (Other solvents such as dilute acetic acid and water can be used for this purpose). The polymer was recovered by precipitation in excess cold methanol. The obtained polymer was dried under dynamic high vacuum for four hours giving 2.2 g of poly (p-vinylbenzylmethacrylate) (90 % yield and purity level is 95%). Gel permeation chromatography equipped with 100Å, 500 Å, 103 Å, 104 Å and one linear µ-ultrastyragel columns showed that the polymer had Mn,Gpc = 19,260 g/mol and Mw/Mn =1.19 with respect to PMMA calibration standards. Mn,cal was 18,700g/mol. 1H NMR of the poly (4-vinylbenzylmethacrylate), taken in CDC13 at 300 MHz, showed the absence of signals at 5.6 ppm and 6.18 ppm corresponding to methacrylate vinyl protons and the presence of 5.2, 5.7 ppm (doublets) and 6.6 ppm (multiplet) corresponding to the styrene moiety of the polymer repeat units. The single proton intensity of the backbone chain and styrene vinyl protons indicates the presence of one styrene group for every repeat unit of the polymer. Example 2 Anionic polymerization of p-vinylbenzylmethacrylate using 1,1-diphenylhexyllithium (DPHLi) as initiator in tetrahydrofuran at -78 °C Into a dry 250 mL round bottom flask equipped with magnetic needle, nitrogen/vacuum three-way adapter with rubber septum, was added 80 mL of dry tetrahydrofuran and the reaction flask was cooled to -78 °C. A tetrahydrofuran solution of 1,1-diphenylhexyllithium (DPHLi) was added drop wise under stirring until the initiator color persisted. Then, 6 ML(5.58 x 10"4 moles) of DPHLi (0.093 M) in tetrahydrofuran was added. After few minutes, 1.1 mL (5.53 x 10-3 mol) of purified p-vinylbenzylmethacrylate (freshly distilled from calcium hydrate) was transferred by stainless steel capillary under stirring using pure nitrogen pressure and the polymerization continued for 15 min. The reaction was terminated by adding degassed methanol. The polymer was recovered by precipitation in excess cold methanol. The obtained polymer was dried under dynamic high vacuum for four hours giving 1.1 g of poly (p-vinylbenzylmethacrylate) (100 % yield and purity level is 95%). Gel permeation chromatography equipped with 100Å, 500 Å, 103 Å, 104 Å and one linearµ-ultrastyragel columns showed that the polymer had Mn,Gpc = 3760 g/mol, Mw/Mn = 1.25 with respect to PMMA calibration standards and the Mn,Cal = 1970 g/mol. Example 3 Anionic block co-polymerization of methylmethacrylate and p- vinylbenzylmethacrylate using 1,1 -diphenylhexyllithium (DPHLi) in presence of lithium perchlorate in tetrahydrofuran at -78 °C Into a dry 250 mL round bottom flask equipped with magnetic needle, nitrogen/vacuum three-way adapter with rubber septum, was added 90 mL of dry tetrahydrofuran. A tetrahydrofuran solution (2 mL) containing 0.200 grams of lithium perchlorate was added and the reaction flask was cooled to -78 °C. A tetrahydrofuran solution of 1,1-diphenylhexyllithium (DPHLi) was added drop wise under stirring until the initiator color persisted. Then, 1.5 mL (1.8 x 10"4 mol) of DPHLi (0.09 M) in tetrahydrofuran solution was added. After few minutes, 3.5 mL (0.037 moles) of purified methylmethacrylate (freshly distilled from a small amount of triethylaluminum solution) was added through stainless steel capillary under stirring using pure nitrogen pressure. After 10 min, a small amount (5mL) of the reaction mixture was taken out using syringe and terminated with methanol and the poly (methyl methacrylate) (first block) was recovered by precipitation in excess -hexane. Then, 0.25 mL (0.0012 moles) p-vinylbenzylmethacrylate (freshly distilled from calcium hydrate) was transferred by stainless steel capillary under stirring using pure nitrogen pressure and the polymerization continued for 10 min. The reaction was terminated by adding degassed methanol. The polymer was recovered by precipitation in excess n-hexane. The crude polymer was dried under dynamic high vacuum for four hours giving 3.5 g of poly (methyl methacrylate-b-p-vinylbenzylmethacrylate) (98 % yield). Gel permeation chromatography equipped with 100Å, 500 Å, 103 Å, 104 Å auu one linear µ,-ultrastyragel columns showed that, the poly (methyl methacrylate) block had Mn,ca, = 23280 g/mol, MW,GPC = 25390 g/mol with Mw/Mn of 1.09 and pel} (methyl methacrylate-b-p-vinylbenzylmethacrylate) had Mn,cal = 24300 g/mol, Mw,GPc = 26840 g/mol with Mw/Mn of 1.09. Example 4 Poly (methyl methacrylate) star polymer by post cross-linking of poly (methyl methacrylate-b-vinylbenzylmethacrylate) using benzylperoxide in toluene at 80 °C. Into a dry 10 mL glass ampoule was added 0.5 grams of poly (methyl methacrylate-b-p-vinylbenzylmethacrylate) (Mn,GPC = 23280 g/mol) and 0.02 grams of benzylperoxide dissolved in 4 mL of dry toluene. The solution was degassed several times using high vacuum and kept under vacuum at 80 °C in an oil batch for 10 h. The reaction was terminated using methanol and the polymer was recovered by precipitation in methanol. The polymer was dried under dynamic high vacuum for 4 h (100 % yield). Gel permeation chromatography equipped with l00Å, 500 Å, 103 Å, 104 Å and one linear µ-ultrastyragel columns showed two peaks corresponding to the precursor di-block copolymer and to the cross-linked product which exhibits broad molecular weight distribution. The star poly (methyl methacrylate) with its precursor di-block copo!, nier had Mn,Gpc = 44600 g/mol, Mw,Gpc = 95700 g/mol and Mw/Mn = 2.14. The present invention has following advantages: 1) The reactive ends of the polymers can be either used for functionalization or used as initiator for the synthesis of functional/di-block polymers. 2) Homo and di-block/statistical copolymers of p-vinylbenzylmethacrylate with controlled molecular weight and narrow molecular weight distribution can be prepared with styrenic group intact on the polymer using anionic initiators. .3) The various di-block copolymers containing reactive double bonds of the p-vinylbenzylmethacrylate segment can be used for post crosslinking reactions using a free radical initiator to form star polymers when used as such or graftcd-network polymers when co-polymerized with other co-monomers. We Claim: 1. A process for the synthesis of reactive polymers and copolymers for p- vinylbenzylmethacrylate which comprises preparing a mixture of organolithium initiator-additive solution such as herein described, wherein the mole ratio of organolithium initiator to additive ranging from 1 : 1 to 1 : 40 cooling the said mixture to -78°C ± 10°C, adding p-vinylbenzylmethacrylate to the organolithium initiator - additive solution under stirring, to obtain a solution of reactive poly (p- vinylbenzylmethacrylate), adding a second monomer selected from the group comprising styrene, alpha-methylstyrene, butadiene, isoprene, alkyl (meth) acrylate such as methyl methacrylate, ethyl methacrylate, n or f-butyl methacrylate, lauryl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and f-butyl acrylate to get a reactive di-block copolymer consisting of p-vinylbenzylmethacrylate segments, terminating the polymerization with degassed methanol and separating the polymer/ co-polymer by conventional precipitation using a non-solvent. 2. A process as claimed in claim 1 wherein the organolithium initiator used is prepared by reacting one mole of n-, secondary, or tertiary- butyllithum with 1,1- diphenylethylene or a-methylstyrene or by direct metalation of methyl or ethyl isobutyrate using lithium diisopropylamide, triphenylmethane by potassium in tetrahydrofuran (THF). 3. A process as claimed in claims 1-2 wherein the additive used is selected from the salt of an alkaline and alkaline-earth metals of acids such as lithiumchloride, lithium perchlorate, or the salt of an alkaline and alkaline-earth metals of mono-, di, tri- and tetra- ethylene glycols or monoalkoxy glycols of above type which can be prepared by the reaction with metallic lithium or by the reaction with an organometallic lithium compound in polar or apolar solvent. 4. A process as claimed in claims 1-3 wherein the solvent used for preparing solution of organolithium initiator-additive is selected from tetrahydrofuran (THF), tetrahydropyran (THP), aromatic hydrocarbon or a mixture of aromatic hydrocarbon and tetrahydrofuran. 5. A process as claimed in claims 1 - 4 wherein the lowest volume % of THF in the mixture is above 5% (v/v), preferably 10%. 6. A process as claimed in claims 1 - 5 wherein the aromatic hydrocarbon used as non-solvent is selected from benzene, toluene, xylene, ethylbenzene, mesitylene and tetralin preferably toluene. 7. A process as claimed in claims 1-6 wherein the mole ratio of organolithium initiator to additive ranging from 1 : 1 to 1 : 40 preferably 1:10. 8. A process for the synthesis of reactive polymers and copolymers from vinylbenzylmethacrylate substantially as herein described with reference to examples accompanying this specification.

Full Text

This invention relates to a process for the synthesis of reactive polymers and copolymers from vinylbenzylmethacrylate. More particularly the present invention relates to a process for the production of reactive polymers and copolymers from p-vinylbenzylmethacrylate with pendent double bonds exhibiting narrow molecular weight distribution using anionic initiator.
Bi-functional monomers having two polymerizable groups are of great interest to polymer chemists. The well-known divinyl monomers are divinylbenzene (1,3- and 1,4- isomers), diisopropenylbenzene (1,3- and 1,4- isomers), ethylenegylcoldimethacrylate, allylmethacrylate, 2-(acryloxy)ethyl methacrylate and p-vinylbenzylmethacrylate. These difunctional monomers are generally used '-polymerization to induce cross-linking (CA 129:140709, EP: 98-100634 (1998) and JP: 95-233771 (1995)). Synthesizing linear polymer from difunctional monomers with one vinyl group intact in every repeating unit is possible in some cases using anionic polymerization (Makromol. Chem. 183, 2787, 1982; Macromolecules, 29, 1753, 1996).
Polymers having polymerizable functional groups at each repeat unit or at its portion of chain segment can be used as reactive polymers in many applications such as cross-linking agent in extruder, controlled post grafting, thermal cross-linking agent in the production of high refractive-index transparent organic glass (JP: 06116336 A2, 1994) and various other polymer composite formulations. Although the reactivity of the two vinyl groups in difunctional monomers differ to certain extent, the initiation source used in many polymerization techniques are more reactive compared to propagating species and does not allow selective initiation of one vinyl group. However, Group Transfer polymerization (GTP) enables the use of silyl

Ketene acetals with a suitable catalyst to initiate only polar vinyl monomer such as alkyl (math)acrylate (J. Am. Chem. Soc., 105, 5706, 1983). Attempts to polymerize p-vinylbenzylmethacrylate through its methacrylate double bond using GTP resulted in low conversions (40 to 81 %) and the polymer exhibited broad molecular weight distribution (MJMn = 8.3) (Polym. Bull.,14, 105, 1985). This indicates that an exclusive polymerization of one vinyl group is not possible by GTP. Linear polymerization of 1,3-diisopropenylbenzene using an anionic initiator in THF at low temperature has been demonstrated (Makromol. Chem., 183, 2787, 1982).
It is known that the reactivity of the two vinyl groups in p-vinylbenzylmethacrylate is widely different. Anionic polymerization of styrene requires a strong initiator like alkyllithium where as a less reactive initiator such as 1,1-diphenylhexyllithium is sufficient to provide a controlled initiation foi methacrylate monomers. The reactivity difference of methacrylic and stryrenic double bonds in p-vinylbenzylmethacrylate provides a means of polymerizing p-vinylbenzylmethacrylate using DPHLi as initiator through its methacrylate group without affecting the styrene group.
The main object of the present invention is, therefore, to provide a process for the synthesis of reactive polymers and copolymers from /?-vinylbenzylmethacrylate, which obviates the drawbacks as detailed above.
Another object is to produce star polymers by post cross-linking of the pendent double bonds of the short blocks of di-block copolymers such as poly (methvlmethacrylate-^-vinylbenzylmethacrylate), poly (styrene-£-vinylbenzyl methacrylate), poly (butadine-fe-vinylbenzylmethacrylate), and poly (isoprene-fc-vinylbenzyl methacrylate) using free radical initiators.

Still another object is to enable the production of grafted-network copolymers by polymerizing di-btock copolymer consisting of short-chain, pendent double bonds with any other comonomers using a free radical initiator.
Accordingly, the present invention provides a process for the synthesis of reactive polymers and copolymers for p-vinylbenzylmethacrylate which comprises preparing a mixture of organolithium initiator-additive solution such as herein described, wherein the mole ratio of organolithium initiator to additive ranging from 1 : 1 to 1 : 40?cooling the said mixture to -78°C + 10°C, adding p-vinylbenzylmethacrylate to the organolithium initiator - additive solution under stirring, to obtain a solution of reactive poly (p- vinylbenzylmethacrylate), adding a second monomer selected from the group comprising styrene, alpha-methylstyrene, butadiene, isoprene, alkyl (meth) acrylate such as methyl methacrylate, ethyl methacrylate, n or f-butyl methacrylate, lauryl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and t-butyl acrylate to get a reactive di-block copolymer consisting of p-vinylbenzylmethacrylate segments, terminating the polymerization with degassed methanol and separating the polymer/ co-polymer by conventional precipitation using a non-solvent.
In an embodiment of the present invention, the organolithium initiator used may be prepared by reacting one mole of n-, secondary, or tertiary-butyllithum with 1,1-diphenylethylene or a- methylstyrene or by direct metalation of methyl or ethyl isobutyrate using lithium diisopropylamide, triphenylmethane by potassium in tetrahydrofuran (THF).
In another embodiment, the additive used may be such as the salt of an alkaline or alkaline-earth metals of acids such as lithium chloride, lithium perchlorate, the salt of an alkaline and alkaline-earth metals of mono-, di-, tri- and tetraethylene glycols or monoalkoxyglycols which can be prepared by reacting with metallic lithium or by the reaction with an organometallic lithium compound in polar or apolar solvent.
In an another embodiment, the solvent used for preparing solution of initiator-additive may be selected from tetrahydrofuran (THF), tetrahydropyran (THP), aromatic hydrocarbon or a mixture of aromatic hydrocarbon and tetrahydrofuran.

In yet another embodiment, the lowest volume % of THF in the mixture is above 5 % (v/v), preferably 10%.
In still another embodiment, the aromatic hydrocarbon may be selected amongst benzene, toluene, xylene, ethylbenzene, mesitylene and tetralin preferably toluene.
In still another embodiment, the mole ratio of organolithium initiator to additive can vary from 1:1 to 1:40 preferably 1:10.
In still another embodiment, the concentration of organolithium initiator may be between 0.3 to 2 millimole/litre and the concentration of p-vinylbenzylmethacrylate is in the range of 0.1 to 0.4 mole/litre.
In another embodiment, the comonomer optionally may be styrene, a-methylstyrene, butadiene, isoprene, alkyl (meth) acrylate such as methyl methacrylate, ethyl methacrylate, n or ?-butyl methacrylate, lauryl methacrylate, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate and r-butyl acrylate.
The process of the present invention is described herein below with examples, which are illustrative only and should not be construed to limit the scope of the invention.

Example 1
Anionic polymerization of p-vinylbenzylmethacrylate, using 1,1-diphenylhexyllithium (DPHLi) in presence of lithium perchlorate in tetrahydrofuran
at -78 °C
Into a dry 250 mL round bottom flask equipped with magnetic needle, nitrogen/vacuum three-way adapter with rubber septum, was added 100 mL of dry tetrahydrofuran. A tetrahydrofuran solution (2 mL) containing 0.200 grams of lithium perchlorate was added and the reaction flask was cooled to -78 °C. A tetrahydrofuran solution of 1,1-diphenylhexyllithium (DPHLi) was added drop wise under stirring until the initiator color persisted. Then, 1.4 mL (1.3 x 10"4 moles) of DPHLi (0.093 M) in tetrahydrofuran was added. After few minutes, 2.4 mL (0.012 moles) of purified p-vinylbenzylmethacrylate (freshly distilled from calcium hydrate) was transferred by stainless steel capillary under stirring using pure nitrogen pressure and the polymerization continued for 15 min. The reaction was terminated by adding degassed methanol. (Other solvents such as dilute acetic acid and water can be used for this purpose). The polymer was recovered by precipitation in excess cold methanol. The obtained polymer was dried under dynamic high vacuum for four hours giving 2.2 g of poly (p-vinylbenzylmethacrylate) (90 % yield and purity level is 95%).
Gel permeation chromatography equipped with 100Å, 500 Å, 103 Å, 104 Å and one linear µ-ultrastyragel columns showed that the polymer had Mn,Gpc = 19,260 g/mol and Mw/Mn =1.19 with respect to PMMA calibration standards. Mn,cal was 18,700g/mol. 1H NMR of the poly (4-vinylbenzylmethacrylate), taken in CDC13 at 300 MHz, showed the absence of signals at 5.6 ppm and 6.18 ppm corresponding to

methacrylate vinyl protons and the presence of 5.2, 5.7 ppm (doublets) and 6.6 ppm (multiplet) corresponding to the styrene moiety of the polymer repeat units. The single proton intensity of the backbone chain and styrene vinyl protons indicates the presence of one styrene group for every repeat unit of the polymer.
Example 2
Anionic polymerization of p-vinylbenzylmethacrylate using 1,1-diphenylhexyllithium (DPHLi) as initiator in tetrahydrofuran at -78 °C
Into a dry 250 mL round bottom flask equipped with magnetic needle, nitrogen/vacuum three-way adapter with rubber septum, was added 80 mL of dry tetrahydrofuran and the reaction flask was cooled to -78 °C. A tetrahydrofuran solution of 1,1-diphenylhexyllithium (DPHLi) was added drop wise under stirring until the initiator color persisted. Then, 6 ML(5.58 x 10"4 moles) of DPHLi (0.093 M) in tetrahydrofuran was added. After few minutes, 1.1 mL (5.53 x 10-3 mol) of purified p-vinylbenzylmethacrylate (freshly distilled from calcium hydrate) was transferred by stainless steel capillary under stirring using pure nitrogen pressure and the polymerization continued for 15 min. The reaction was terminated by adding degassed methanol. The polymer was recovered by precipitation in excess cold methanol. The obtained polymer was dried under dynamic high vacuum for four hours giving 1.1 g of poly (p-vinylbenzylmethacrylate) (100 % yield and purity level is 95%).
Gel permeation chromatography equipped with 100Å, 500 Å, 103 Å, 104 Å and one linearµ-ultrastyragel columns showed that the polymer had Mn,Gpc = 3760 g/mol, Mw/Mn = 1.25 with respect to PMMA calibration standards and the Mn,Cal = 1970 g/mol.

Example 3
Anionic block co-polymerization of methylmethacrylate and p-
vinylbenzylmethacrylate using 1,1 -diphenylhexyllithium (DPHLi) in presence of
lithium perchlorate in tetrahydrofuran at -78 °C
Into a dry 250 mL round bottom flask equipped with magnetic needle, nitrogen/vacuum three-way adapter with rubber septum, was added 90 mL of dry tetrahydrofuran. A tetrahydrofuran solution (2 mL) containing 0.200 grams of lithium perchlorate was added and the reaction flask was cooled to -78 °C. A tetrahydrofuran solution of 1,1-diphenylhexyllithium (DPHLi) was added drop wise under stirring until the initiator color persisted. Then, 1.5 mL (1.8 x 10"4 mol) of DPHLi (0.09 M) in tetrahydrofuran solution was added. After few minutes, 3.5 mL (0.037 moles) of purified methylmethacrylate (freshly distilled from a small amount of triethylaluminum solution) was added through stainless steel capillary under stirring using pure nitrogen pressure. After 10 min, a small amount (5mL) of the reaction mixture was taken out using syringe and terminated with methanol and the poly (methyl methacrylate) (first block) was recovered by precipitation in excess -hexane. Then, 0.25 mL (0.0012 moles) p-vinylbenzylmethacrylate (freshly distilled from calcium hydrate) was transferred by stainless steel capillary under stirring using pure nitrogen pressure and the polymerization continued for 10 min. The reaction was terminated by adding degassed methanol. The polymer was recovered by precipitation in excess n-hexane. The crude polymer was dried under dynamic high vacuum for four hours giving 3.5 g of poly (methyl methacrylate-b-p-vinylbenzylmethacrylate) (98 % yield).
Gel permeation chromatography equipped with 100Å, 500 Å, 103 Å, 104 Å auu one linear µ,-ultrastyragel columns showed that, the poly (methyl methacrylate) block

had Mn,ca, = 23280 g/mol, MW,GPC = 25390 g/mol with Mw/Mn of 1.09 and pel} (methyl methacrylate-b-p-vinylbenzylmethacrylate) had Mn,cal = 24300 g/mol, Mw,GPc = 26840 g/mol with Mw/Mn of 1.09.
Example 4
Poly (methyl methacrylate) star polymer by post cross-linking of poly (methyl methacrylate-b-vinylbenzylmethacrylate) using benzylperoxide in toluene at 80 °C.
Into a dry 10 mL glass ampoule was added 0.5 grams of poly (methyl methacrylate-b-p-vinylbenzylmethacrylate) (Mn,GPC = 23280 g/mol) and 0.02 grams of benzylperoxide dissolved in 4 mL of dry toluene. The solution was degassed several times using high vacuum and kept under vacuum at 80 °C in an oil batch for 10 h. The reaction was terminated using methanol and the polymer was recovered by precipitation in methanol. The polymer was dried under dynamic high vacuum for 4 h (100 % yield).
Gel permeation chromatography equipped with l00Å, 500 Å, 103 Å, 104 Å and one linear µ-ultrastyragel columns showed two peaks corresponding to the precursor di-block copolymer and to the cross-linked product which exhibits broad molecular weight distribution. The star poly (methyl methacrylate) with its precursor di-block copo!, nier had Mn,Gpc = 44600 g/mol, Mw,Gpc = 95700 g/mol and Mw/Mn = 2.14.
The present invention has following advantages:
1) The reactive ends of the polymers can be either used for functionalization or used
as initiator for the synthesis of functional/di-block polymers.
2) Homo and di-block/statistical copolymers of p-vinylbenzylmethacrylate with
controlled molecular weight and narrow molecular weight distribution can be
prepared with styrenic group intact on the polymer using anionic initiators.

.3) The various di-block copolymers containing reactive double bonds of the p-vinylbenzylmethacrylate segment can be used for post crosslinking reactions using a free radical initiator to form star polymers when used as such or graftcd-network polymers when co-polymerized with other co-monomers.

We Claim:
1. A process for the synthesis of reactive polymers and copolymers for p-
vinylbenzylmethacrylate which comprises preparing a mixture of organolithium
initiator-additive solution such as herein described, wherein the mole ratio of
organolithium initiator to additive ranging from 1 : 1 to 1 : 40 cooling the said
mixture to -78°C ± 10°C, adding p-vinylbenzylmethacrylate to the organolithium
initiator - additive solution under stirring, to obtain a solution of reactive poly (p-
vinylbenzylmethacrylate), adding a second monomer selected from the group
comprising styrene, alpha-methylstyrene, butadiene, isoprene, alkyl (meth)
acrylate such as methyl methacrylate, ethyl methacrylate, n or f-butyl
methacrylate, lauryl methacrylate, methyl acrylate, ethyl acrylate, n-butyl
acrylate, 2-ethylhexyl acrylate and f-butyl acrylate to get a reactive di-block
copolymer consisting of p-vinylbenzylmethacrylate segments, terminating the
polymerization with degassed methanol and separating the polymer/ co-polymer
by conventional precipitation using a non-solvent.
2. A process as claimed in claim 1 wherein the organolithium initiator used is
prepared by reacting one mole of n-, secondary, or tertiary- butyllithum with 1,1-
diphenylethylene or a-methylstyrene or by direct metalation of methyl or ethyl
isobutyrate using lithium diisopropylamide, triphenylmethane by potassium in
tetrahydrofuran (THF).
3. A process as claimed in claims 1-2 wherein the additive used is selected from the
salt of an alkaline and alkaline-earth metals of acids such as lithiumchloride,
lithium perchlorate, or the salt of an alkaline and alkaline-earth metals of mono-,
di, tri- and tetra- ethylene glycols or monoalkoxy glycols of above type which can

be prepared by the reaction with metallic lithium or by the reaction with an organometallic lithium compound in polar or apolar solvent.
4. A process as claimed in claims 1-3 wherein the solvent used for preparing
solution of organolithium initiator-additive is selected from tetrahydrofuran (THF),
tetrahydropyran (THP), aromatic hydrocarbon or a mixture of aromatic
hydrocarbon and tetrahydrofuran.
5. A process as claimed in claims 1 - 4 wherein the lowest volume % of THF in the
mixture is above 5% (v/v), preferably 10%.
6. A process as claimed in claims 1 - 5 wherein the aromatic hydrocarbon used as
non-solvent is selected from benzene, toluene, xylene, ethylbenzene, mesitylene
and tetralin preferably toluene.
7. A process as claimed in claims 1-6 wherein the mole ratio of organolithium
initiator to additive ranging from 1 : 1 to 1 : 40 preferably 1:10.
8. A process for the synthesis of reactive polymers and copolymers from
vinylbenzylmethacrylate substantially as herein described with reference to
examples accompanying this specification.

Documents:

568-del-2000-abstract.pdf

568-del-2000-claims.pdf

568-del-2000-correspondence-others.pdf

568-del-2000-correspondence-po.pdf

568-del-2000-description (complete).pdf

568-del-2000-form-1.pdf

568-del-2000-form-19.pdf

568-del-2000-form-2.pdf

568-del-2000-form-3.pdf

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Patent Number

216747

Indian Patent Application Number

568/DEL/2000

PG Journal Number

13/2008

Publication Date

31-Mar-2008

Grant Date

19-Mar-2008

Date of Filing

09-Jun-2000

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	DURAIRAJ BASKARAN	NATIONAL CHEMICAL LABORATORY, PUNE-411008, INDIA.

PCT International Classification Number

C07C 69/54

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA