Title of Invention	A PROCESS FOR THE PREPARATION OF CONDUCTING CO-POLYMER HAVING ENHANCED THERMAL STABILITY
Abstract	The present invention provides a process for preparation of conducting co-polymer having enhanced thermal stability, which comprises dissolving a monomer or an oligomer chosen from aromatic compounds in known organic polar solvents and adding strong electron acceptors and a co-monomer chosen from macrocyclic compounds having cation binding property. The monomer or the oligomer is chosen from aromatic sulfur compounds such as polyphenylene sulfide, diphenyl sulfide, thiophene and the like. The co-monomer is chosen from the macrocyclic compounds having cation binding property, containing substituted groups such as chlorinated phthalocyanine, phthalocyanine carboxylate, chloro-porphyrin and the like.

Title of Invention

A PROCESS FOR THE PREPARATION OF CONDUCTING CO-POLYMER HAVING ENHANCED THERMAL STABILITY

Abstract

The present invention provides a process for preparation of conducting co-polymer having enhanced thermal stability, which comprises dissolving a monomer or an oligomer chosen from aromatic compounds in known organic polar solvents and adding strong electron acceptors and a co-monomer chosen from macrocyclic compounds having cation binding property. The monomer or the oligomer is chosen from aromatic sulfur compounds such as polyphenylene sulfide, diphenyl sulfide, thiophene and the like. The co-monomer is chosen from the macrocyclic compounds having cation binding property, containing substituted groups such as chlorinated phthalocyanine, phthalocyanine carboxylate, chloro-porphyrin and the like.

Full Text	This mvention relates to a proces for synthesis of conducting polymers having enhanced thermal stability Conducting polymers are technologically important materials. However, in order to use these for practical applications, these are required to have stable conductivity with respect to high temperature thermal cycling. As for example, during moulding of the polymer it is subjected to heat treatment from room temperature to processing temperature in excess of 160°C. The conductivity for the most of the conventional conducting polymer is found to decrease considerably after such heat treatment. The prior art for improving the stability of conductivity in conducting polymers is blending them with other polymers such as polystyrene, polyvinyl chloride, nylon etc. (J. Margolis, Handbook of Conducting Polymers and Plastics, Chapman & Hall, New York 1989 ) or by composite formation (S.Radhakrishnan et al, Polymer Inter.34,111,1994, Synthetic Met.79,2]9,1996, Ind.Pat.Appl. 287/DEL/95). In the earlier reports the process of formation of conducting polymer composites comprises first dissolving the bulk polymer in a solvent to which are added strong electron acceptors, casting the sheet of these activated polymers, exposing these to vapours of monomers having heterocyclic moieties, drying the same to obtain conducting polymer having room temperature stability. However, these, methods yield a material having .heterogeneous phase morphology and discontinuities. This is not always desirable since heterogeneous morphology carTlead to many side effects such as nonlinear response to voltage, solvent absorption and instability with respect to chemical vapours etc. The overall conductivity also is reduced from its value in original polymer. Co-polymerization with different monomers such as styrene, vinyl chloride etc. has not been found to be very successful in improving the properties of conducting polymers It has been observed that the thermal stability of the conducting polymers is enhanced by incorporation of certain co-monomer which binds to the conducting polymer as well as the dopant ions. The object of the present invention is to provide a process for the preparation of conducting co-polymer having enhanced thermal stability. Accordingly, the present invention provides a process for preparation of conducting co-polymer having enhanced thermal stability, which comprises dissolving a monomer or an oligomer chosen from aromatic compounds such as herein described in known organic polar solvents, adding strong electron acceptors and a co-monomer chosen from macrocyclic compounds having cation binding property in the ratio of 0.1 to 0.6, the ratio of co-monomer to monomer is in the range of 0.1 to 1.0, keeping the mixture for 2 to 8 hrs at atmospheric pressure at a temperature ranging between 25 to 200°C, allowing the reaction mixture to cool to room temperature, pouring the reaction mixture in non-solvent for precipitation of co-polymer, separating the precipitated co-polymer by conventional methods, then drying for a period ranging between 4 to 6 hrs at temperature ranging between 60 to 100°C and further exposing the same to conventional doped ions by known methods for a period of 12 to 20 hrs at ambient temperature to obtain the conducting polymer having enhanced thermal stability. In one of the embodiments of the present invention, the monomer or the oligomer is chosen from aromatic sulfur compounds such as polyphenylene sulfide, diphenyl sulfide, thiophene and the like. In another embodiment of the present invention, the co-monomer is chosen from the macrocyclic compounds having cation binding property, containing substituted groups such as chlorinated phthalocyanine, phthalocyanine carboxylate, chloro-porphyrin and the like. In the preferred range of composition of 20% to 50% mol of the co-monomer, the conducting co-polymer has stable conductivity even after thermal cycling, its degradation temperature is considerably increased and the weight loss at certain high temperature (excess of 300 degree C) is markedly decreased. trie constant polar solvent such as nitro benzene, n-methyl pyrrolidone and the like. In still another embodiment of the present process, the dopant employed may be halogen containing electron acceptor such as iodine, bromine and chlorine and is used along with an aromatic solvent. In another feature of the present invention, ratio of co-monomer to monomer is in the range of 0.1 to 1.0 mole/mole preferably 0.2 to 0.5 . In the preferred range of composition of 20% to 50% mol of the co-monomer, the conducting co-polymer has stable conductivity even after thermal cycling, its degradation temperature is considerably increased and the weight loss at certain high temperature ( excess of 300° C) is markedly decreased. The invention is described hereinbelow with reference to examples, which are illustrations only and should not be construed to limit the scope of the present invention in any manner. EXAMPLE - 1 Low molecular weight polyphenylene sulfide oligomers having molecular weight of about 750 ( d.p. = 7 to 8) ( 0.4 gms) were dissolved in 12 ml of n- methyl pyrrolidinone to which were added sodium sulfide (0.128 gms) and chlorinated copper-phthalocyanine (0.085 gms). The reaction mixture was placed in a glass ampule which was then sealed. The temperature was increased to 180°C and reaction allowed to proceed for 4 hrs. The whole mass was dumped into methanol and the co-polymer filtered, washed and dried. The co-polymer (0.25 gms) was placed in the iodine solution in benzene (12 wt %) for 24 hrs when it got incorporated with the dopant ions. The doped conducting co-polymer was filtered crushed and dried at room temperature. The properties of this co-polymer are indicated in Table - 1. EXAMPLE - 2 Phenylene sulphide was first formed by reacting in situ the p-dichlorobenzene (0.102 gms) dissolved in n-methyl pyrrolidinone (14.4 ml) to which were added 0.166 gms Na2S and then chlorinated copper-phthalocyanine (0.45 gms) was added to the same. The whole reaction mixture was stirred and placed in a glass ampule which was subsequently sealed. The temperature was raised to 180°C and reaction allowed to proceed for 4 hrs. The whole mass was dropped into methanol and the precipitated co-polymer filtered, washed 'and dried. The co-polymer (0.3 gms) was placed in the iodine solution (12 wt%) in benzene for 24 hrs so as to incorporate it with the dopant. The doped co-polymer was filtered and dried at room temperature. The properties of this co-polymer are indicated in Table - 1. EXAMPLE - 3 Ferric chloride (9.75 gms) was dissolved in nitrobenzene (100 ml) to which were added 0.285 gm of chlorinated copper-phthalocyanine. Nitrogen gas was bubbled through the mixture for 1 hr and 1.7 ml of thiophene were slowly dropped in the reaction mixture. The reaction was allowed to proceed under flow of nitrogen at room temperature for 1 hr. The resulting mass • ' was precipitated in-methanol, -washed, crushed and-dried. The co-polymer (0.3 gms) was placed in the iodine solution (12 wt %) in benzene for 20 hrs. The doped co-polymer was filtered and dried at room temperature. The properties of this co-polymer are indicated in Table- Table -1 (Table Removed) It may be observed from the above data in Table-1 that the stability of conducting polymer is considerably improved as compared to the original homopolymer when the co-monomer is present in the reaction mixture. The conductivity is also found to increase after heat treatment in some cases. Thus the co-polymer formation as described in the present invention leads to enhanced thermal stability in conducting polymers,. In certain preferred range of composition and reaction conditions the conductivity obtained was high and stable to number of temperature cycling. WE CLAIM: 1. A process for the preparation of conducting co-polymer having enhanced thermal stability, which comprises dissolving a monomer or an oligomer chosen from aromatic compound such as herein described in known organic polar solvents, adding strong electron acceptors and a co-monomer chosen from macrocyclic compounds having cation binding property in the ratio of 0.1 to 0.6, the ratio of co-monomer to monomer is in the range of 0.1 to 1.0, keeping the mixture for 2 to 8 hrs at atmospheric pressure at a temperature ranging between 25 to 200s, allowing the reaction mixture to cool to room temperature, pouring the reaction mixture in non- solvent for precipitation of co-polymer, separating the precipitated co-polymer by conventional methods, then drying for a period ranging between 4 to 6 hrs at temperature ranging between 60 to 100°C and further exposing the same to conventional doped ions by known methods for a period of 12 to 20 hrs at ambient temperature to obtain the conducting polymer having enhanced thermal stability. 2. A process as claimed in claim 1, wherein the monomer or the oligomer is chosen from aromatic sulfur compounds such as polyphenylene sulfide, diphenyl disulfide, thiophene. 3. A process as claimed in claim 1, wherein the co-monomer is chosen from the macrocyclic compounds having cation binding property and containing substituted groups such as chlorinated phthalocyanine, phthalocyanine carboxylate, chloro-porphyrin. 4. A process as claimed in claim 1, wherein the strong electron acceptors such as cupric chloride, ferric chloride are used for initiators. 5. A process as claimed in claim 1, wherein the doped ion used is chosen from halogen containing electron acceptors such as iodine, bromine, chlorine, ferric chloride, arsenic pentafluoride. 6. A process as claimed in claim 1, wherein the solvent used for preparing solution of the monomer is chosen from high dielectric constant polar solvent such as n-methyl pyrrolidone, nitrobenzene. 7. A process as claimed in claim 1, wherein the ratio of co-monomer to monomer is preferably 0.2 to 0.5 mole/mole. 8. A process for the preparation of conducting co-polymer having enhanced thermal stability, substantially as herein described with reference to the examples.

Full Text

This mvention relates to a proces for synthesis of conducting polymers having enhanced thermal stability
Conducting polymers are technologically important materials. However, in order to use these for practical applications, these are required to have stable conductivity with respect to high temperature thermal cycling. As for example, during moulding of the polymer it is subjected to heat treatment from room temperature to processing temperature in excess of 160°C. The conductivity for the most of the conventional conducting polymer is found to decrease considerably after such heat treatment. The prior art for improving the stability of conductivity in conducting polymers is blending them with other polymers such as polystyrene, polyvinyl chloride, nylon etc. (J. Margolis, Handbook of Conducting Polymers and Plastics, Chapman & Hall, New York 1989 ) or by composite formation (S.Radhakrishnan et al, Polymer Inter.34,111,1994, Synthetic Met.79,2]9,1996, Ind.Pat.Appl. 287/DEL/95). In the earlier reports the process of formation of conducting polymer composites comprises first dissolving the bulk polymer in a solvent to which are added strong electron acceptors, casting the sheet of these activated polymers, exposing these to vapours of monomers having heterocyclic moieties, drying the same to obtain conducting polymer having room temperature stability. However, these, methods yield a material having .heterogeneous phase morphology and discontinuities. This is not always desirable since heterogeneous morphology carTlead to many side effects such as nonlinear response to voltage, solvent absorption and instability with respect to chemical vapours etc. The overall conductivity also is reduced from its value in original polymer. Co-polymerization with different monomers such as styrene, vinyl chloride etc. has not been found to be very successful in improving the properties of conducting polymers
It has been observed that the thermal stability of the conducting polymers is enhanced by incorporation of certain co-monomer which binds to the conducting polymer as well as the dopant ions.

The object of the present invention is to provide a process for the preparation of conducting co-polymer having enhanced thermal stability.
Accordingly, the present invention provides a process for preparation of conducting co-polymer having enhanced thermal stability, which comprises dissolving a monomer or an oligomer chosen from aromatic compounds such as herein described in known organic polar solvents, adding strong electron acceptors and a co-monomer chosen from macrocyclic compounds having cation binding property in the ratio of 0.1 to 0.6, the ratio of co-monomer to monomer is in the range of 0.1 to 1.0, keeping the mixture for 2 to 8 hrs at atmospheric pressure at a temperature ranging between 25 to 200°C, allowing the reaction mixture to cool to room temperature, pouring the reaction mixture in non-solvent for precipitation of co-polymer, separating the precipitated co-polymer by conventional methods, then drying for a period ranging between 4 to 6 hrs at temperature ranging between 60 to 100°C and further exposing the same to conventional doped ions by known methods for a period of 12 to 20 hrs at ambient temperature to obtain the conducting polymer having enhanced thermal stability.
In one of the embodiments of the present invention, the monomer or the oligomer is chosen from aromatic sulfur compounds such as polyphenylene sulfide, diphenyl sulfide, thiophene and the like.
In another embodiment of the present invention, the co-monomer is chosen from the macrocyclic compounds having cation binding property, containing substituted groups such as chlorinated phthalocyanine, phthalocyanine carboxylate, chloro-porphyrin and the like.
In the preferred range of composition of 20% to 50% mol of the co-monomer, the conducting co-polymer has stable conductivity even after thermal cycling, its degradation temperature is considerably increased and the weight loss at certain high temperature (excess of 300 degree C) is markedly decreased.

trie constant polar solvent such as nitro benzene, n-methyl pyrrolidone and the like.
In still another embodiment of the present process, the dopant employed may be halogen containing electron acceptor such as iodine, bromine and chlorine and is used along with an aromatic solvent.
In another feature of the present invention, ratio of co-monomer to monomer is in the range of 0.1 to 1.0 mole/mole preferably 0.2 to 0.5 .
In the preferred range of composition of 20% to 50% mol of the co-monomer, the conducting co-polymer has stable conductivity even after thermal cycling, its degradation temperature is considerably increased and the weight loss at certain high temperature ( excess of 300° C) is markedly decreased.
The invention is described hereinbelow with reference to examples, which are illustrations only and should not be construed to limit the scope of the present invention in any manner.
EXAMPLE - 1
Low molecular weight polyphenylene sulfide oligomers having molecular weight of about 750 ( d.p. = 7 to 8) ( 0.4 gms) were dissolved in 12 ml of n- methyl pyrrolidinone to which were added sodium sulfide (0.128 gms) and chlorinated copper-phthalocyanine (0.085 gms). The reaction mixture was placed in a glass ampule which was then sealed. The temperature was increased to 180°C and reaction allowed to proceed for 4 hrs. The whole mass was dumped into methanol and the co-polymer filtered, washed and dried. The co-polymer (0.25 gms) was placed in the iodine solution in benzene (12 wt %) for 24 hrs when it got incorporated with the dopant ions. The doped conducting co-polymer was filtered crushed and dried at room temperature. The properties of this co-polymer are indicated in Table - 1.

EXAMPLE - 2
Phenylene sulphide was first formed by reacting in situ the p-dichlorobenzene (0.102 gms) dissolved in n-methyl pyrrolidinone (14.4 ml) to which were added 0.166 gms Na2S and then chlorinated copper-phthalocyanine (0.45 gms) was added to the same. The whole reaction mixture was stirred and placed in a glass ampule which was subsequently sealed. The temperature was raised to 180°C and reaction allowed to proceed for 4 hrs. The whole mass was dropped into methanol and the precipitated co-polymer filtered, washed 'and dried. The co-polymer (0.3 gms) was placed in the iodine solution (12 wt%) in benzene for 24 hrs so as to incorporate it with the dopant. The doped co-polymer was filtered and dried at room temperature. The properties of this co-polymer are indicated in Table - 1.
EXAMPLE - 3
Ferric chloride (9.75 gms) was dissolved in nitrobenzene (100 ml) to which were added 0.285 gm of chlorinated copper-phthalocyanine. Nitrogen gas was bubbled through the mixture for 1 hr and 1.7 ml of thiophene were slowly dropped in the reaction mixture. The reaction was allowed to proceed under flow of nitrogen at room temperature for 1 hr. The resulting mass
*• '
*was precipitated in-methanol, -washed, crushed and-dried. The co-polymer (0.3 gms) was placed in the iodine solution (12 wt %) in benzene for 20 hrs. The doped co-polymer was filtered and dried at room temperature. The properties of this co-polymer are indicated in Table-

Table -1
(Table Removed)
It may be observed from the above data in Table-1 that the stability of conducting polymer is considerably improved as compared to the original homopolymer when the co-monomer is present in the reaction mixture. The conductivity is also found to increase after heat treatment in some cases. Thus the co-polymer formation as described in the present invention leads to enhanced thermal stability in conducting polymers,.
In certain preferred range of composition and reaction conditions the conductivity obtained was high and stable to number of temperature cycling.

WE CLAIM:
1. A process for the preparation of conducting co-polymer having enhanced thermal stability,
which comprises dissolving a monomer or an oligomer chosen from aromatic compound such
as herein described in known organic polar solvents, adding strong electron acceptors and a
co-monomer chosen from macrocyclic compounds having cation binding property in the ratio
of 0.1 to 0.6, the ratio of co-monomer to monomer is in the range of 0.1 to 1.0, keeping the
mixture for 2 to 8 hrs at atmospheric pressure at a temperature ranging between 25 to 200s,
allowing the reaction mixture to cool to room temperature, pouring the reaction mixture in non-
solvent for precipitation of co-polymer, separating the precipitated co-polymer by conventional
methods, then drying for a period ranging between 4 to 6 hrs at temperature ranging between
60 to 100°C and further exposing the same to conventional doped ions by known methods for
a period of 12 to 20 hrs at ambient temperature to obtain the conducting polymer having
enhanced thermal stability.
2. A process as claimed in claim 1, wherein the monomer or the oligomer is chosen from
aromatic sulfur compounds such as polyphenylene sulfide, diphenyl disulfide, thiophene.
3. A process as claimed in claim 1, wherein the co-monomer is chosen from the macrocyclic
compounds having cation binding property and containing substituted groups such as
chlorinated phthalocyanine, phthalocyanine carboxylate, chloro-porphyrin.
4. A process as claimed in claim 1, wherein the strong electron acceptors such as cupric chloride,
ferric chloride are used for initiators.
5. A process as claimed in claim 1, wherein the doped ion used is chosen from halogen
containing electron acceptors such as iodine, bromine, chlorine, ferric chloride, arsenic
pentafluoride.
6. A process as claimed in claim 1, wherein the solvent used for preparing solution of the
monomer is chosen from high dielectric constant polar solvent such as n-methyl pyrrolidone,
nitrobenzene.
7. A process as claimed in claim 1, wherein the ratio of co-monomer to monomer is preferably 0.2
to 0.5 mole/mole.
8. A process for the preparation of conducting co-polymer having enhanced thermal stability,
substantially as herein described with reference to the examples.

Documents:

1975-del-1998-abstract.pdf

1975-del-1998-claims.pdf

1975-del-1998-correspondence-others.pdf

1975-del-1998-correspondence-po.pdf

1975-del-1998-description (complete).pdf

1975-del-1998-form-1.pdf

1975-del-1998-form-19.pdf

1975-del-1998-form-2.pdf

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Patent Number

232901

Indian Patent Application Number

1975/DEL/1998

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

21-Mar-2009

Date of Filing

10-Jul-1998

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	SHRIPAD DAGDOPANT DESHPANDE	INDIAN NATIONALS OF NATIONAL CHEMICAL LABORATORY PUNE, INDIA.
2	SUBRAMANIAM RADHAKRISHNAN	INDIAN NATIONALS OF NATIONAL CHEMICAL LABORATORY PUNE, INDIA.

PCT International Classification Number

C08F 232/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA