STUDY ON THE BLENDS OF NYLON 66 AND LIQUID CRYSTALLINE POLYESTERS

Blends of polyamide (Nylon 66) with two different kinds of liquid crystalline polyesters were studied in all the composition range. Homogeneous samples were obtained by coprccipitation from 2 wt%. solution of blends. The thermal properties, crystallinity and morphology of these blends were studied by using DSC, polarizing microscopy, and scanning electron microscopy. The phase transition and morphology of the blends are markedly-influenced by the composition of liquid crystalline polyesters. The mechanical behaviour of PHB/HNA-Nylon 66 blend was improved. although polyamidc (Nylon 66)with the liquid crystalline polyesters were incompatible, but a rather strong interaction between the polymers did exist.     

环氧树脂/聚氨酯共混体系相行为研究

利用小角光散射 (SALS)技术实时记录了环氧树脂 聚氨酯共混体系在固化过程中的相行为发展情况 ,得到了表征共混体系相区结构尺寸大小的相关距离ac 和表征体系均匀程度的均方介电常数涨落 η2 ,讨论了等温固化条件下 ,环氧树脂 聚氨酯共混体系的相区大小随时间的变化规律 .实验结果表明 ,环氧树脂 聚氨酯共混体系的固化过程是典型的反应诱导相分离的过程 .相分离初期 ,符合Cahn的线性理论 ;随着固化时间的延长 ,相区由小变大 ,约至反应开始后 3 2 1 0s,相分离趋于平衡态 ,相区尺寸趋于稳定     

Influence of compatibilization on the mechanical behavior of poly(trimethylene terephthalate)/poly(ethylene-octene) blends

Poly(trimethylene terephthalate) (PTT) based blends toughened with up to 30 wt.% of a partially maleinized poly(ethylene-octene) copolymer (mPEO) were obtained by melt mixing. The blends were composed of two pure amorphous phases and a partially crystalline PEO phase. The rubber modification clearly compatibilized the blends leading to a decrease in the dispersed phase size. The decrease was not enough to attain the brittle-tough transition, but an increase in the shear rate gave rise to an additional decrease in the dispersed phase size and in the interparticle distance (IDc) that led to very high toughness values (15-fold the notched impact strength of the matrix) at rubber contents above 25 wt.%. The critical interparticle distance of the blends was 0.17 μm. A comparison between this IDc and those of PBT/mPEO and PET/mPEO blends was explained in terms of their interfacial tensions.     

聚氧化乙烯-聚苯乙烯-聚氧化乙烯三嵌段共聚物/聚苯醚共混物的相容性和结晶行为

本工作对聚氧化乙烯-聚苯乙烯-聚氧化乙烯(PEO-PS-PEO)三嵌段共聚物与聚苯醚(PPO)均聚物共混物的相容性及结晶行为进行了研究。结果表明,共混体系的相容性与嵌段共聚物中苯乙烯段的含量有关,PS含量越高,PPO与共聚物PS段的相容性越好。共混体系的结晶行为也明显不同于一般均聚物共混体系。在DSC降温结晶过程中最多可出现三个结晶峰。     

乙丙橡胶/聚丙烯共混体系的界面相互渗透

本文用X射线衍射仪、差热分析仪、动态力学扭摆仪和测定有效网链密度等方法,研究了乙丙橡胶/聚丙烯(EPDM/PP)共混体系中PP的非晶部分和EPDM的相互渗透。EPDM和PP不具有互溶性,但PP的非晶部分和EPDM两相界面处有较强的相互渗透,即部分互容性。有效链密度和性能间关系的数据表明,共混体系不一定存在硫化胶那样的对应关系。     

PROPERTIES OF SILK FIBROIN/POLY(ETHYLENE GLYCOL)400 BLEND FILMS

The blend film of silk fibroin (SF) and poly(ethylene glycol)400 (PEG400) with a blend ratio of 2/1 (wt/wt) wasprepared simply by dropping a little PEG400 into the SF solution and then casting the mixed aqueous solution at 50℃. Theresulting film exhibited much better mechanical properties in the dry and wet state than SF itself, owing to theconformational change of SF in the blends from the random coil to the β-sheet structure and intermolecular hydrogen bondformation between SF and PEG400. Thermogravimetric analysis showed that the initial thermal decomposition temperatureof the blend film was 170℃, which was 80℃ lower than that of SF (250℃) and 20℃ higher than that of PEG400 (150℃),and indicated a Strong interaction between two components of the blend. No crystalline peaks were observed in the X-raydiffraction curve of the blend film. Cell culture test showed that SF/PEG400 was a suitable substrate for the growth of humanumbilical vein endothelial cells (HUVEC).     

L-聚乳酸/低分子量壳聚糖共混膜的制备和特性

二甲基亚砜(DMSO)作为共溶刺，将两种极性不同的生物医用高分子L-聚乳酸(PLLA)与低分子量壳聚糖混合在一起．扫描电镜(SEM)研究结果表明两种组分共混时存在着明显的相分离．当壳聚糖含量在2％以内时，壳聚糖相在共混膜中呈现空心圆状的图案，空心圆的直径为几微米．PLLA用DMSO溶解后，在重新干燥的过程中，PLLA的堆积结构会发生变化，它的玻璃化转变温度由55.5℃变为34℃．共混膜中混入的壳聚糖含量在2％以内时，在保持的聚乳酸的力学性能的同时。可以降低聚乳酸的接触角。改善聚乳酸的亲水性．     

Effect of P(MMA-co-MAA) compatibilizer on the miscibility of nylon 6/PVDF blends

With the ultimate objective of enhancing the impact strength and weatherability of nylon 6 engineering plastic, blending with poly(vinylidene fluoride) (PVDF) was studied. In the absence of a compatibilizer the two polymers phase separate, resulting in a deterioration of the properties. Since poly(methyl methacrylate) is known to be miscible with PVDF, we evaluated poly(methyl methacrylate-co-methacrylic acid) (P(MMA-co-MAA)) of low methacrylic acid content as the compatibilizer. The carboxylic acid groups in the MAA units were expected to react with the end amino groups of nylon 6 forming block or graft copolymers, P(MMA-co-MAA)-g-nylon 6, in situ, which will function as the actual compatibilizer. The amount of P(MMA-co-MAA) added, the MMA/MAA composition and heat treatment time were varied to study their effects on the miscibility, morphology, and mechanical properties of nylon 6/PVDF blends. The enhancement of the compatibility of nylon 6 and PVDF by addition of P(MMA-co-MAA) and the partial miscibility of nylon 6 and PVDF has been confirmed through DSC, dynamic mechanical testing, SEM of fracture surfaces, and tensile testing. The decrease in the crystallization temperatures on addition of compatibilizer in DSC experiments suggests that the compatibilizer enhances the interaction between the two components and retards the crystallization. The dynamic mechanical thermal analysis experiments suggest that the compatibility in the amorphous regions of nylon 6 and PVDF in particular has been enhanced. The increase in the heat treatment time in the molten state resulted in further enhancement of the miscibility. The enhancement of compatibility by addition of a reactive compatibilizer and heat treatment resulted in a significant increase in the energy of rupture in tensile testing.     

含环氧基的丙烯酸酯弹性体的合成及其对聚氯乙烯改性研究

以丙烯酸丁酯（ＢＡ），甲基丙烯酸甲酯（ＭＭＡ）和甲基丙烯酸缩水甘油酯（ＧＭＡ）为原料，通过分段乳液聚合，合成了一系列具有不同组成结构的三元共聚物—Ｐ（Ｂ—Ｍ—Ｇ）弹性体，并对此弹性体改性的ＰＶＣ的抗冲击性能进行了系统研究．结果表明：改性剂组成结构的变化对改性体系的冲击性能有较大影响，改性ＰＶＣ的冲击性能最高可达７９ｋＪ／ｍ２．动态力学及ＳＥＭ实验表明，ＰＶＣ与改性体系系部分相容的共混体系，其断裂行为是明显的韧性断裂特征．本文还对改性体系的力学性能进行了研究．     

聚酰胺1010／聚乙烯－马来酸酐接枝共聚物共混物力学和热学性能研究

为了表明马来酸酐接枝聚烯烃后对聚酰胺的相容作用，本文研究了聚酰胺１０１０（ＰＡ１０１０）／聚乙烯－马来酸酐接枝共聚物（ＰＥ－ｇ－ＭＡＨ）共混物在不同ＭＡＨ接枝量下的结晶性与力学性能。研究表明，ＭＡＨ的存在导致ＰＥ－ｇ－ＭＡＨ－ｃｏ－ＰＡ１０１０共聚物的形成，而该共聚物在标题共混物中起着相容剂的作用。共混物的结晶性能变化显示了共混组分间存在一定程度的混溶性。在一定的ＭＡＨ含量内，标题共混物具有协同效应。