The Synthesis And Properties Of The Low-molecular-weight Styrene-Malic Anhydride Copolymer

Poly (styrene-maleic anhydride)(SMA)is a kind of structure can be regulated and easy functionalization polymer which includes nonpolar phenyl group and polar carboxyl group. Excellent compatibility with hydrophobic and hydrophilic material. So it can be used to modify some materials with low surface energy and low polarity.A series of SMA with different molecular weight were prepared by precipitation polymerization with mixed solvent of butyl acetate and n-heptane, AIBN as initiator,3-mercaptopropionic acid as chain transfer agent, styrene and maleic anhydride as comonomer. Effect factors of polymerization such as reaction temperature, reaction time, initiator dosage, chain transfer agent dosage, monomer molar ratio were investigated in this dissertation. The structure of SMA was characterized by means of FTIR、1HNMR、13CNMR.The molecular weight and the distribution of the copolymer were tested by GPC And its thermo-performance was analyzed by DSC and TG.The results show that the yield of SMA reach maximum when n (St/MAH) ratio is1:1; The molecular weight (Mn) of SMA decrease with elevating temperature, increasing dosage of initiator and chain transfer agent, and improving n (St/MAH) ratio.The chemical structure of SMA was characterized by FTIR and NMR, suggesting SMA is mainly alternate copolymer. The thermo-performance of copolymer was characterized by TG and DSC, showing that the low-molecular-weight SMA copolymer shows good hot endurance performance. The glass transition temperature is about145℃, the decompose temperature of copolymer is more than300℃.The thermal decomposition kinetic of the SMA/E-51was studied with Kissinger. function approaches. The calculations show that thermal decomposition apparent activation energy of the SMA/E-51is104.3kJ/mol, The pre-exponential factor is1.83×l07min-1The contact angles of water, diiodomethane and ethylene glycol on SMA/E-51blend membranes and their surface free energy with different molecular weights of SMA are studied. The results show that mixing-ratio of SAM to E-51, and molecular weight of SMA have little or no impact on surface free energy.