Study On Synthesis And Properties Of Functional Polysiloxanes

Compared with cationic curing,radical curing has the characteristics of fast curing speed and not particularly affected by moisture.Meanwhile polysiloxanes have some unique physical and chemical properties such as remarkable thermal and thermo oxidative resistance,weather and solvent resistance,biological inertness and much better resistance to electromagnetic and particle radiation(UV,alpha,beta and gamma rays)than organic plastics.The thiol-ene reaction has been specifically applied in polysiloxane due to its fast curing rate and its ability to eliminate the oxygen inhibition.In this thesis,the acrylate-based MTQ resin was synthesized by hydrolysis copolymerization method.The obtained resin was characterized by FT-IR,1H-NMR and GPC.The effects of the molar ratio of M,T and Q units on the thermal stability and molecular weight of synthetic resins were investigated.The source of the trifunctional T unit was changed toγ-mercaptopropyltriethoxysilane(KH-580)to obtain a mercapto-based MTQ resin.The obtained resin was characterized.The effect of changing the molar ratio of MM on the molecular weight and thermal stability of the resin was studied.The thermal degradation products of the mercapto-based MTQ resin were also characterized.The acrylate-based MTQ resin was cured with a 1-hydroxycyclohexyl phenyl ketone(184)as an initiator under a UV lamp of 36 W and 5 mW/cm2.The double bond conversion of the acrylate-based resin and the thermal stability,transmittance,contact angle and hardness of the cured film of acrylate-based resin were investigated.As a difunctional resin,TPGDA has a long induction period when cured,and the cured film has a low transmittance,a small contact angle,and poor thermal stability.After modification with an acrylate-based MTQ resin,the related properties are improved.The modification of TPGDA with a mercapto-based MTQ resin can also accelerate the reaction rate and increase the conversion rate of the double bond.At the same time,as the resin is added,the transmittance and contact angle of the cured film are increased,and the thermal stability is also improved.When PETMP is mixed with acrylate-based MTQ resin,the compatibility is not good.According to the principle of similar compatibility,the addition of mercapto-based MTQ resin has good compatibility.In this thesis,the effect of the addition of mercapto-based MTQ resin on the contact angle and thermal stability of acrylate-based MTQ resin was investigated.