Study On Acid Sensitive Gelatinization Reaction Of Amidino Polysiloxane

The silicone oxygen bond on the backbone of the amino polysiloxane can be flexibly rotated,the flexibility of the framework is very high,its glass transition temperature is relatively low about 120 degrees below zero.Because its excellent oxidation resistance and thermal stability,it has a wide range of applications.However,the interaction between the molecular chains is relatively small,the molar volume is relatively large,showing high ductility and low viscosity,this is a lack of its practical application.Such as its relatively low mechanical properties,it is difficult to be processed into stable fibers and films,so they need to be modified such as cross-linking.Over the past few decades,people are trying to improve this defect,but the methods are very complex,So we think of introducing electrostatic force into its system.Firstly,we use it to synthesize amidino polysiloxane,to improve its alkaline,then we introducing CO2 into the mixed system of amidino/amino polysiloxane to prepare a CO2 responsive gel system.Secondly,We use amino polysiloxane to react with organic carboxylic,the viscosity and modulus of the system are improved by introducing the electrostatic force into the system.If the organic carboxylic acid is a dibasic acid,the two adjacent polysiloxane backbone can be linked to each other through a carboxyl amidine salt bridge to form a crosslinked network structure,improving the inter molecular interaction and its rheological properties.At the same time,we think that photo acid can be introduced into the system of amidino polysiloxane/amino polysiloxane to produce a photo-responsive gel.We take CO2 into the amidino/amino polysiloxane mixed system,the viscosity of system can be increased to 105 Pa-s.One hours later,the storage modulus is greater than its loss modulus,indicating that the system has been completely gelled.Amidino polysiloxane has a relatively large increase of its viscosity after adding the monoacid into the system.even if the amidino polysiloxane butyrate,its viscosity is 32 times of the pure amidino polysiloxane,the viscosity of amidino polysiloxane acetate is highest,its viscosity can be increased to 102 Pa·s.In general,the viscosity of the amidino polysiloxane carboxylate was significantly larger than the pure amidino polysiloxane.The shorter the segment of the carboxylic acid,the greater the viscosity.The viscosity and modulus of amidino polysiloxane dicarboxylate system are improved to a greater extent.The viscosity of oxalate can be increased to the order of 103-104 Pa-s,and its storage modulus can beincreased to the order of 103Pa·s.In general,the dibasic acid salt system can form a cross-linked network structure,the rheological properties are significantly better than the amidino polysiloxane monoacid system.The viscosity,modulus and other properties of the amidino polysiloxane dibasic acid salt system are mainly related to the length of the carboxylic acid segment,while related with the molecular structure of the carboxylic acid,the viscosity and modulus of carboxylate formed by odd carbon atom carboxylic acid is relatively low.According to the study of CO2 responsive amidino polysiloxane gel and amidino polysiloxane carboxylate system,we have developed a rapid photo responsive gel system,Its viscosity and modulus gradually increase with the illumination time.The more the content of photoacid,the higher increasing rate of viscosity and modulus,the higher storage modulus of the gel.