聚对二氧环己酮/聚乙二醇两亲性聚合物共网络的合成与表征

以辛酸亚锡为催化剂,季戊四醇(PTOL)为引发剂,引发对二氧环己酮(PDO)单体开环聚合,合成了以PTOL为核的四臂聚对二氧环己酮(4s-PPDO).通过直接将4s-PPDO预聚物和聚乙二醇(PEG)于熔点以上、惰性气体保护下与偶联剂甲苯二异氰酸酯(TDI)交联共聚得到聚对二氧环己酮/聚乙二醇(PPDO-b-PEG)两亲性共网络聚合物(PPDO-PEG APCNs).研究了两亲性聚合物共网络结构、配比组成、溶剂种类等对聚合物溶胀率的影响,结果表明APCNs在不同类型的溶剂中表现出不同的溶胀行为,可以通过调节偶联剂的用量及PPDO/PEG的投料比来满足不同的实际需求.通过示差扫描量热分析(DSC)详细研究APCNs的结晶性能,证实交联反应降低APCNs的结晶度和结晶尺寸.

SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC POLYMER CONETWORKS BASED ON POLY(P-DIOXANONE) AND POLY(ETHYLENE GLYCOL)

A series of amphiphilic polymer conetworks(APCNs) composed of poly(ethylene oxide)(PEG) and poly(p-dioxanone)(PPDO) segments were synthesized and characterized.Four-arm star-shaped poly(p-dioxanone)(4s-PPDO) precursor with hydroxyl terminal group was prepared by ring-opening polymerization of PDO using stannous 2-ethylhexanoate Sn(Oct)2 ] as a catalyst and pentaerythritol(PTOL) as initiator.Amphiphilic PPDO-b-PEG conetworks were prepared by directly coupling reaction of the hydroxyl group terminated 4s-PPDO and PEG precursors using toluene 2,4-diisocyanate(TDI) as chain extender.The influences of molecular structure,type of solvents on the swelling ratio of the amphiphilic PPDO-b-PEG conetworks were studied.The co-continuity of the conetworks was characterized via swelling in chloroform,tetrahydrofuran and H2O,respectively,and the results show that amphiphilic PPDO-b-PEG polymer networks had different swelling behaviors in different solvents,which were determined by the dosage of coupling agent and feed ratio of PPDO /PEG.The crystalline behaviors of copolymers were studied by differential scanning calorimetry(DSC).The results indicated that compositions of PPDO and PEG and the degree of crosslinking,which were obtained by using various amount of TDI,had an important influence on the thermal and crystalline behaviors such as melting temperature(Tm),crystallizing temperature(Tc),melting enthalpy(ΔHm),crystallizing enthalpy(ΔHc),and degree of crystallinity.The crosslinking structure limited the crystallization of PEG segments,resulting in decreased relative degree of crystallization and crystal size.