Poly(tetramethylene oxide)-coated silica nanoparticles incorporated into poly(4,4′-oxydiphenylene-pyromellitimide) matrix

Telechelic poly(teramethylene oxide) with two isocyanate end groups (OCN-PTMO-NCO) was synthesized by the reaction of polytetrahydrofuran (M_n?=?1000?g?mol^?1) and hexamethylene diisocyanate in 1:2 molar ratio. The resulting macrochains were then covalently grafted to the surface of silica nanoparticles (SNPs). Thus, the inorganic nanoparticles could be thoroughly coated by a thick and soft organic shell. Thermogravimetric measurements showed that up to 85?wt.% of the organically modified SNPs (OSNPs) could be formed from the organic part. Different weight ratios of OSNPs were subsequently added to a solution of 4,4′-oxydiphenylamine/pyromellitic dianhydride poly(amic acid) (PAA) in dimethylformamide. Chemical cyclodehydration of the PAA in the presence of homogeneously dispersed OSNPs resulted in poly(4,4′-oxydiphenylene-pyromellitimide) (POPI) nanocomposites, labeled by POPI/OSNP 5, POPI/OSNP 7.5, and POPI/OSNP 10. The nanocomposites obtained were fully characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. According to the diffuse reflectance UV spectroscopy, in comparison with neat POPI, the POPI/OSNP series showed an appreciable redshift in the λ_max values up to 15–20?nm. Moreover, POPI/OSNP series showed significant stability toward heat at temperatures above 540°C. The endothermic phase transitions occurred by the first thermodegradation of the resulting nanocomposites could be obviously seen in the differential thermal analysis.     

基于聚四氢呋喃的形状记忆聚氨酯的合成及形状记忆性能

采用两步法合成了以聚四氢呋喃(PTMG)为软段,4,4′-二苯基甲烷二异氰酸酯(MDI)、扩链剂2,2-二羟甲基丙酸(DMPA)和封端剂4-(2-(吡啶-4-基)乙烯基)苯酚为硬段的形状记忆聚氨酯(PTMGUs)。通过傅里叶变换红外光谱和核磁共振氢谱等表征了其结构,将聚氨酯制成薄膜后,分别通过热重分析、差示扫描量热及循环拉力动态力学分析等测试研究了硬段含量对其热性能和形状记忆性能的影响,摄像记录其形状回复过程。结果表明,不同硬段含量的PTMGUs都具有较好的形状记忆性能,4次重复形状记忆循环中PTMGUs的平均固定率与回复率都高于90%,其中PTMGU3(硬段质量分数为35%)的形状记忆性能最佳,平均固定率达到96.9%,平均回复率达到99.5%。     

长碳链聚酰胺1012弹性体的合成与表征

利用双端羧基封端的聚酰胺1012（PA1012）与聚四氢呋喃醚二醇（PTMG）熔融嵌段共聚合,合成了聚酰胺1012型的热塑性弹性体（TPAE）。采用傅里叶变换红外光谱确定合成了PA1012-b-PTMG嵌段共聚物,采用广角X射线衍射对其结晶性进行了分析,采用差示扫描量热分析、热失重分析、力学性能测试、溶解性分析等方法对弹性体的性能进行了表征。结果表明,合成的PA1012-PTMG弹性体,具有较高的熔点（＞180 ℃）与较高的热分解温度（＞420 ℃）,力学性能与耐溶剂性能优异,是一种性能优异的热塑性弹性体材料。     

低熔点PET-PTMG共聚醚酯的合成与表征

将对苯二甲酸二甲酯(DMT)、间苯二甲酸二甲酯(DMI)、乙二醇(EG)、新戊二醇(NPG)进行酯交换反应后,再与聚四氢呋喃醚(PTMG)进行缩聚反应,制得低熔点共聚醚酯。采用傅里叶变换红外光谱(FT-IR)、核磁共振氢谱(1H-NMR)、差示扫描量热分析(DSC)、动态热力学分析(DMA)对共聚醚酯的结构与性能进行了表征。结果表明:在其他条件相同时,随NPG比例的增加,共聚醚酯的粘度增大,其NPG与EG链段比值提高,玻璃化转变温度(Tg)升高。当nDMT:nDMI为1:1,nNPG:nEG为3.3:6.7,PTMG质量分数为31.9%时,制得的共聚醚酯的Tg为25.79℃,熔点约130℃;35℃时,共聚醚酯贮能模量最大,耐热性能较好。     

聚四氢呋喃生产过程中分子量控制的影响因素

分析了美国英威达工艺生产PTMEG产品时的分子量控制影响因素。通过对聚合反应的醋酸、醋酸酐浓度、进料量及控制窄化工序(SPD)温度,具体介绍了PTMEG分子量影响因素及控制方法。     

低分子量聚四氢呋喃二苯甲酸酯的增塑性能分析

以传统的邻苯二甲酸二辛酯（DOP）和聚醚型二甘醇二苯甲酸酯（DEDB）增塑剂作对比,对聚四氢呋喃二苯甲酸酯（PTMGDB₅₀₀）增塑剂增塑的聚氯乙烯（PVC）材料进行研究。本文对增塑剂增塑的PVC材料进行了FTIR和TG表征,并考察了其力学性能、耐乙醇抽出性及耐迁移性。结果表明,增塑剂PTMGDB₅₀₀增塑的PVC材料在力学性能上介于DOP和DEDB两者之间,而PTMGDB₅₀₀与PVC间的相互作用更强,在耐迁移、耐乙醇抽出、耐热及耐压等性能方面均优于DOP及DEDB,因此PTMGDB₅₀₀可作为部分替代DOP和DEDB的增塑剂。     

端羧基四氢呋喃聚醚改性环氧树脂的研究

采用端羧基四氢呋喃聚醚(CTPTHF)作为双酚A型环氧树脂的增韧剂或改性剂,以含芳环的脂肪族多元胺改性物为固化剂,讨论了聚醚添加量(以每100g树脂中添加的聚醚质量计)对环氧树脂固化物的热性能、力学性能及粘接性能的影响。实验结果表明,CTPTHF的引入,明显改善了环氧体系的抗冲击性能、粘接性能。在低添加量范围内(如10%～20%),改性以增韧为主,在高添加量范围内(如30%以上),改性以增柔为主。通过观察环氧树脂体系固化过程中浊度变化和按均相共聚物混合规律计算出的玻璃化转变温度与实测值对照,以及扫描电子显微镜观察分析,初步认为CTPTHF改性环氧树脂固化物是非均相结构,形成以环氧树脂为连续相,聚醚为分散相的两相结构形态。     

四氢呋喃均聚醚催化研究进展(续)

<正> (接上期第12页)3.2.2 无定型硅酸铝 硅酸铝是经过广泛研究的典型的二元氧化物,固体酸的概念也是通过对硅酸铝的研究而建立起来的。SiO2/AI2O3上的酸中心强度比H0=-8.2还强,且同时具有B酸和L酸2种酸型。20世纪90年代初,ARCO公司的Kahn[60]使用羧酸酐/无定型硅酸铝为催化体系,合成PTMEG。使用的羧酸酐可以是乙酸酐、内酸酐、邻苯二甲酸酐和马来酸酐。硅酸铝中铝质量分数为10％-30％,比表面积20-500m2/g。产物相对分子质量为200-5000,分布指数在3以下。     

均匀设计法研究聚四氢呋喃的阳离子开环聚合制备工艺

采用高氯酸/乙酸酐引发四氢呋喃阳离子开环聚合制备出聚四氢呋喃,并用均匀设计法研究了各工艺参数的影响,通过多元逐步回归的方法对结果进行分析得到聚四氢呋喃产物相对分子质量的预测方程,同时评价了聚合过程中高氯酸加入量、乙酸酐加入量及聚合时间对产物相对分子质量和相对分子质量分布的影响。研究发现,在选取的研究范围内,乙酸酐加入量、高氯酸加入量和聚合时间对聚四氢呋喃产物相对分子质量影响的显著性依次降低,其中聚合时间的影响可以忽略;聚四氢呋喃的相对分子质量分布则几乎不受工艺参数的影响。     

Polyurethanes from renewable resources. IV–properties of linear,crosslinked and segmented polymers from polytetrahydrofuran diols and their glucosides

Various types of polyurethanes were synthesised from two classes of polyols: (i) 1,4-butane diol or selected polytetrahydrofuran (PTHF) diols of different average molecular weights in the range ～300–2300; (ii) mono- or bisglucosides derived from each of these diols. Linear or crosslinked polymers were prepared by reaction with diphenylmethane diisocyanate (MDI) and the properties of polymers from each class of polyol were compared. Higher PTHF molecular weights produced better properties for the diol based materials whereas lower (parent) PTHF molecular weights favoured the glucoside based materials. Segmented polymers were prepared from reaction with MDI and the chain extender ethylene glycol (EG). Manipulation of the cure conditions and hard block concentration produced materials of widely differing properties. At certain hard block concentrations and using rapid (high temperature) curing the glucoside based materials were (i) superior in properties to the diol based materials and (ii) had similar properties to commercial reaction injection moulding polyurethanes.