Study Of Cationic Copolymerization Of Styrene And Pinene Using Phosphotungstic Acid Supported By Activated Carbon

Heteropolyacids have attracted much attention because of it’s advantages such as strong acidity, pseudoliquid phase and multifunction. Heteropolyacids could used as acid-base and redox catalysts in homogeneous and heterogeneous systems. Heteropolyacids’catalytic activity and thermostability have been improved after immobilization, and easy to recycle and reuse. It can promote the catalytic reaction.Turpentine is one of the most abundant renewable natural resources in the world; and it is particularly rich in China. α-Pinene and β-pinene are the major constituents of turpentine. But most of them were used as primary products which had low additional value. So it is become main research topic how to improve the quality and class of turpentine nowadays.The use of turpentine is extensive, and more applications are prepared terpene resin by polymerization.In this dissertation, Keggin phosphotungstic acid which supported by activated carbon have been used as heterogeneous catalyst in the cationic copolymerization of turpentine, α-pinene and β-pinene with styrene. The main research methodes and results are as bellow:1) A series of supported PW12/C with activated carbon as support have been prepared via reflux and used as heterogeneous catalysts in the cationic copolymerization of a-pinene and styrene. The structure, surface morphology and the acidity of the prepared PW12/C catalysts were investigated by FT-IR、XRD、NH3-TPD and SEM. The results revealed that the PW]2highly dispesed on the surface of activated carbon and still kept its Keggin structure after immobilization. Meanwhile, the acidic amount increased with the increase of supported amount of PW12, which contributes to the enhancement of catalytic activity. Furthmore, polymerization conditions were optimized as follows:The volume of α-pinene1.6, styrene3.4mL, polymerization temperature is20℃, reaction time is2h, the amount of PW12/C catalyst which dehydrated at100℃for0.5h is0.7g (supported amount25.4%), the amount of1,2-dichloroethane7mL. Under these conditions, the copolymer product yield obtained was79.1%. Through the characterization of FI-IR、GPC、1H-NMR、TG-DTG and DSC to copolymer, it can been seen that the molecular weight of copolymer is810, and it’s distribution is1.35; and the copolymer has high thermostability.2) The copolymer of (3-pinene and styrene was synthesized. The suitable copolymerization conditions were confirmed by studying the effects on copolymer reaction:the molar ratio of (3-pinene to styrene1:1, the amount of catalyst (PW12/C) is0.8g (supported amount25.1%), reaction temperature is0℃, reaction time is7h, roasting temperature is150℃, roasting time is2h, the amount of1,2-dichloroethane4mL. Under these conditions, the copolymer product yield obtained was70.3%. From the GPC, the average molecular weight is867and it’s distribution is1.38.3) The copolymer of turpentine and styrene was synthesized. Furthmore, polymerization conditions were optimized as follows:The volume of1.0mL, styrene4.0mL, reaction temperature is20℃, reaction time is5h, the amount of1,2-dichloroethane is3mL, the amount of PW12/C catalyst which dehydrated at100℃for2h is0.8g (supported amount25.7%). Under these conditions, the copolymer product yield obtained was up to86.4%. the average molecular weight of copolyer is about900and it’s distribution is1.45.