Preparation And Characterization Of Elastomers Containing Organic Fluorosilicone Moities

Organic fluorosilicone material is a kind of high-performance material with Si-O-Si main chain and fluorine-containing groups in the side chain.Due to possessing fluorine-containing groups and Si-O-Si main chains,organic fluorosilicone material exhibits excellent performance,such as excellent high and low temperature resistance,fuel and solvent resistance and light stability.Therefore,organic fluorosilicone materials have developed rapidly in the industry,and have been widely used in various fields.A series of new fluorosilicone materials can be obtained by ring-opening polymerization and the introduction of functional groups using fluorosilicone monomers.In this paper,1,3,5-trimethyl-1,3,5-（3,3,3-trifluoropropyl）cyclotrisiloxane（D₃F）,hexamethyl cyclotrisiloxane（D3）,1,3,5-triethyl cyclotrisiloxane（D₃Vi）and tetramethyl divinyl siloxane（Mvi Mvi）were used as raw materials and solid base was used as catalyst to make fluorosilicone raw rubber.High molecular weight fluorosilicone rubber was prepared by anion ring-opening polymerization and the reaction conditions（temperature and time）were optimized.It was found that high molecular weight and stable fluorosilicone raw rubber could be obtained by controlling the appropriate temperature.The results showed that under the conditions of 90℃,when the amount of catalyst was 0.2%of the total feed,the reaction time was 10 min,and the amount of D₃F was 80%,the molecular weight was the highest,which was 820,000 by using Ubbelohde viscometer.Secondly,via ring opening polymerization,amino-capped fluorosilicone oil was prepared by using D3F as raw material,1,3-bis（3-aminopropyl）-1,1,3,3-tetramethyldisiloxane as end-capping agent.The structure of the amino-capped fluorosilicone oil was characterized by FTIR and ¹H NMR spectra.The degree of polymerization of amino fluorosilicone oil was calculated by ¹H NMR.Furthermore,A series of thermoplastic polyurethane elastomers（TPUs）were prepared by using the amino-capped fluorosilicone oil and 1,4-butanediol（BDO）as chain extenders to reaction with 1,4-Phenylene diisocyanate（PPDI）prepolymer（PPDI-PTMEG 1000）.The effect of the contents of fluorosilicone oil on the mechanical and thermal properties of TPU was studied.The results show that the modified TPU has higher storage modulus at low temperature than the TPU without fluorosilicon chain.The modified TPU has better thermal stability when the addition amount of fluorosilicon oil is 10%,and the 5%weight loss temperature is 317.2℃.Compared with pure BDO as chain extender,the tensile strength and elongation at break are increased by 15.3%and 12.4%respectively.