Synthesis Of Linear And Star Epichlorohydrin Rubber By Neodymium Catalyst System

Epichlorohydrin rubber has the same excellent performance with other synthetic ru-bber such as nitrile rubber, neoprene rubber, besides it also has unique semi-conductive properties. This performance of epichlorohydrin rubber as the roller rubber parts is widel-y used in printers, copiers and other office automation products. Hence, the synthesis of novel high performance epichlorohydrin rubber is concerned. In this paper, the di(2-ethyl hexyl) phosphonate neodymium salt Nd(P204)3 (Nd), triisobut-ylaluminum Al(i-Bu)3 (Al), and water (H2O) consisting of ternary rare earth catalytic system (Nd/Al/H2O) was used. The homopolymerization of epichlorohydrin and the copolymerization of epichloroh-ydrin/ethylene oxide were investigated. A series of novel linear、star-epichlorohydrin homopolymer and epichlorohydrin/ethylene oxide copolymer were synthesized successfu-lly. The varieties and properties of epichlorohydrin rubber were enriched and expanded.In toluene solution, the realization rules of epichlorohydrin (ECH) homopolymerizati-on were studied by ternary rare earth catalytic system (Nd/Al/H2O) and the linear、star-epichlorohydrin homopolymer were synthesized successfully. The effects of molecular weight and thermodynamic properties of ECH homopolymerization were detailed inspe-ction by [Al]/[Nd] ratio, the amount of monomer etc.; at the same time, the effects of the molecular weight、molecular weight distribution and thermodynamic properties of star ECH polymer by the amount and type of coupling agent. The results were showed: only when [Al]/[Nd]>4:1, the polymerization reaction was active, and with the [Al]/[Nd] ratio increased, the polymerization activity was increased gradually, besides the conversion rate was presented linear growth; the control of polmer molecular weight was realized by adjusting [Al]/[Nd] ratio, the form of water as the third component catalyst, the am-ount of monomer; star ECH polymer was synthesized using two kinds of coupling age nts:diglycidyl ether of ethylene glycol (EGDE), p-(2,3-epoxy propoxy)-N, N-bis (2,3 epoxy propyl) aniline (TGAP) by Nd/Al/H2O catalyst. Different number arms of star ECH polymer was synthesized through changing types and amount of coupling agent; the Tg and thermal decomposition property of star polymer were little influenced with two types of coupling agent.Based on the study of ECH polymerization, the catalytic performance of Nd/Al/H2O catalyst for ECH/ethylene oxide (EO) copolymerization was studied. The influence of copolymeric conversion rate, molecular weight and its distribution, composition and thermal properties were systematic studied by catalyst composition、monomer ratio、the amount of water、type and amount of solvent; at the same time, the effects of the amount of coupling agent and the form of water on the synthesis of star ECH/EO copolymer were studied and its properties were characterized. The results were showed:only when the ratio of [Al]/[Nd] was higher than 5:1, ECH/EO polymerization having catalytic activity was catalyzed by Nd/Al/H2O; the polymerization conversion rate of [Al]/[Nd] was sho-wed a parabolic change, and the highest activity was presen-ted when [Al]/[Nd]=30:1;by changing the [Al]/[Nd] ratio, the molecular weight of the copolymer could be regulated and controlled; the third component H2O was necessary while the change of water cont-ent was little effected on the structure of polmer, and the highest activity was presented when [H2O]/[Nd]=7.2:1; when the [Nd]:[Al]:[H2O]=1:35:3.6, changing the amount of ECH/EO, ECH composition can be controlled in the range of 20-80%; different number of arms for ECH/EO star copolymers were synthesized using TGAP coupling agent by Nd/Al/H2O catalyst; in the synthesis of star copolymer, the coupling efficiency was higher by using crystal water than liquid water.