耐热型聚苯乙烯微球的制备

通过苯乙烯和二乙烯基苯(DVB)自由基共聚方法合成了聚苯乙烯(PS)微球,并采用热交联方法对产物进行高温热处理,制备了耐热型聚苯乙烯微球。差示热分析和傅里叶红外光谱分析表明,热处理前DVB的添加量从5.5%增加到15%,其产物的玻璃化转变温度(Tg)基本保持在117℃左右不变;高温热处理使悬挂在聚合物分子链上的乙烯基双键发生自由基聚合交联反应,产物的交联密度提高,Tg明显提高,并且随着DVB添加量的增加Tg不断上升。产物热处理温度越高所需热处理时间越短,但是温度过高或时间过长,分子链会发生热降解副反应,导致Tg下降,较优的热处理条件为195℃时热处理1h。

Preparation of Heat-Resisting Polystyrene Microspheres

The random copolymer polystyrene(PS) microspheres were prepared with styrene and divinyl benzene (DVB) by suspension polymerization,which was followed by thermal-curing to improve the heat-resisting performance.The samples were characterized by FT-IR spectrometer and differential scanning calorimetry(D S C).The results show that the glass transition temperature(Tg) remains a constant at about 117 ℃ with the increased mass fraction of DVB from 5.5 ％ to 15.0 ％ before heat treatment.Heat method can significantly improve its Tg,and the Tg increases with the increased content of DVB.High temperature reacted on vinyl bonds which were hanging on PS molecular chains to cause crosslinking density improved by radical crosslinking polymerization.The required heat time is decreased with increasing heat temperature,and thermal degradation may occur on the molecular chains when time and temperature exceed certain point.In this study,it is found the optimal heat condition is 195 ℃ and1 h.