高密度聚乙烯/尼龙6共混物的形态结构对其性能的影响

本文利用微层共挤方法制备了具有层状交替结构的HDPE/PA6共混物,利用常规熔融共混挤出方法制备了与层状共混物具有相同组成比的海岛结构共混物。通过DSC,FT-IR及力学性能测试等方法研究了共混物的形态结构对其界面化学反应、结晶行为和力学性能的影响。研究结果表明:在共混物中引入少量马来酸酐接枝高密度聚乙烯时,化学反应在界面进行,与海岛结构的共混物界面面积相比,层状共混物的界面接触面积小,界面化学反应相对较弱,但层状共混物的屈服强度和断裂伸长率有大幅度提高。层状结构对HDPE和PA6的结晶行为影响很小。     

聚对苯二甲酸乙二醇酯-聚酰胺嵌段共聚物/聚酰胺6共混物的流变性能

通过熔融共混挤出的方法,制备了不同共聚比例的聚对苯二甲酸乙二醇酯-聚酰胺嵌段共聚物(PET-PA)与聚酰胺6(PA6)的共混物,采用毛细管流变仪对PET-PA/PA6共混物的流变性能进行了研究。结果表明,PET-PA/PA6共混物熔体为剪切变稀的非牛顿流体。随温度升高,PET-PA/PA6共混物熔体的表观黏度下降,非牛顿指数增大,表观黏度对剪切速率的敏感性减小,因此升高温度能改善共混物熔体的流动性能。随PET-PA中PA共聚比例的增加,PET-PA/PA6共混物的黏度减小,非牛顿指数增大,这为开发酸性染料可染聚酯纤维提供了参考。     

微层共挤出PP/EVOH共混物的阻隔性能

利用微层共挤出技术对聚丙烯(PP)/乙烯-乙烯醇共聚物(EVOH)共混物进行二次加工,制备出了气体阻隔性能显著提高的PP/EVOH共混复合材料。通过电子扫描显微镜、气体渗透实验研究了微层共挤出共混物的形态结构及其对共混物阻隔性能的影响。研究结果表明,微层共挤出技术能够有效调节EVOH分散相在PP基体中的形态结构,随着层数的增加,使其从零维球形变形为一维纤维状,进而演变成二维片状,这些形态导致128层微层共挤出共混物的气体阻隔性能较普通共混物提高了52倍。     

改性马来酸酐橡胶接枝物增韧尼龙6的制备及表征

为了促进橡胶接枝物与尼龙6(PA6)的相容性并提高增韧效果,利用马来酸酐和对苯二胺合成了一种含酰胺键的二元羧酸,命名为对苯马来二酰胺二酸(改性马来酸酐,MDMA),并将MDMA接枝到三元乙丙橡胶(EPDM)上,制备出不同接枝率的改性马来酸酐橡胶接枝物(EPDM-g-MDMA),以EPDM-g-MDMA与PA6质量比为30∶70,通过共混挤出制备了含不同接枝率接枝物的EPDM-g-MDMA/PA6共混物。通过核磁共振和红外光谱对MDMA进行了测试,表明成功合成了所需要的二元羧酸。对共混物进行了相容性测试、DSC、熔融指数(MI)、SEM、拉伸和冲击力学性能测试。结果表明:随着接枝率的增大,共混物的熔融峰温度略有降低,其熔体黏度不断增大,橡胶接枝物在PA6基体中有良好的分散性,使EPDM-g-MDMA/PA6共混物的冲击强度提高了5.5倍,说明EPDM-g-MDMA对PA6的增韧效果较为明显。     

PP和PP/POE交替多层共混物的结构与力学性能

通过微纳层状共挤出技术制备了聚丙烯(PP)和PP/POE交替多层共混物。通过扫描电镜、差示扫描量热分析、动态力学分析以及力学性能测试对比研究了交替多层共混物和PP/POE普通共混物的结构与力学性能的关系。结果表明,与含有相同乙烯-辛烯共聚物(POE)含量的普通共混物相比,交替多层共混物的低温冲击强度(-40℃)、弯曲强度和弯曲模量都得到了明显的提升。由于在交替多层结构中刚性的PP层和韧性的PP/POE层能够相互支撑,使得材料获得了优异的综合性能。     

新型相容剂EVALM增容PA6／LDPE共混体系的研究

制备了新型尼龙/聚烯烃相容剂EVALM,并用双螺杆挤出机制备了PA6/LDPE和PA6/LDPE/EVALM共混物,对其进行了DSC、SEM、DMA和拉伸性能的测试。研究结果表明,EVALM能通过与PA6的氨基产生氢键缔合或反应而提高PA6/LDPE的相容性,EVALM的加入影响了PA6相的结晶度和玻璃化转变温度,减小了分散相尺寸,提高了共混物的拉伸性能。     

热致液晶共聚酯/PA6/RSMA原位复合材料1.RSMA对热致液晶共聚酯/PA6共混体系的增容作用

选用Vectra A950热致液晶共聚酯（LCP）,制备热致液晶共聚酯（LCP）／聚酰胺6（PA6）／苯乙烯－马来酸酐无规共聚物（RSMA）三元共混物,采用注射成型的方法实现原位复合,测定复合材料的熔体流变性能,FTIR光谱,动态力学性质和共混物形态结构,研究了RSMA对聚酰胺6／热致液晶共聚酯共混体系的增容作用,结果表明,RSMA的加入提高了LCP／PA6共混体的熔体粘度：RSMA与LCP和PA6发生酯化,酰胺化反应,改善了LCP与PA6之间的相容性,使两者的玻璃化温度相互靠近,了LCP在PA6基体中的分散,增强了两者之间的界面粘接。     

PTFE/PA6和PTFE/PA66共混物的吸水性及流变行为

通过浸水实验、缺口冲击断裂实验和动态流变测试,考察了PTFE含量对PTFE/PA6和PTFE/PA66共混物的吸水率、冲击断裂强度及熔体黏度的影响以及熔体黏度随温度和频率的变化规律。结果表明,PTFE/PA6和PTFE/PA66共混物的吸水率均随着PTFE含量的增加而减小,即PTFE的加入抑制了共混物的吸水性。两种共混物的冲击强度比纯PA明显降低,但是吸收水对两种共混物冲击强度的影响不显著。随着PTFE含量的增加,共混物熔体的黏度先减小后增加,说明适量的PTFE可以改善共混物的成型加工特性。共混物熔体的黏度随加载频率的增大而降低,符合假塑性流体流动规律。有趣的是,对于PTFE/PA6共混物的黏度随着温度的升高而减小,而PTFE/PA66共混物黏度随着温度升高近似成指数规律增大。     

HDPE/PA6共混阻隔材料的制备及研究

采用熔融挤出法制备了高密度聚乙烯(HDPE)与马来酸酐(MAH)的接枝物(HDPE-g-MAH),并用红外光谱证实了接枝反应。以此接枝物为相容剂制备HDPE/PA6共混材料。研究了PA6和相容剂用量对共混材料形态结构、力学性能及阻气性能的影响。SEM表明相容剂可以明显改善HDPE与PA6的相容性。PA6的加入显著提高了HDPE对氧气的阻隔性能。     

反应增容PA6/PBT共混体系聚集态结构与力学性能

通过熔融共混制备了SMA增容的PA6/PBT共混物,研究了增容剂对PA6/PBT共混体系聚集态结构及力学性能的影响。研究表明,SMA能有效地提高PA6/PBT共混体系两相间的相容性,降低分散相尺寸,使分散相分布均匀,同时有效地提高了共混体系的力学性能。通过对试样进行热处理,探讨了不同热处理温度对PA6/PBT共混合金力学性能的影响。结果表明,热处理能提高共混物的拉伸强度,但导致共混物的缺口冲击强度下降。     

紫外线辐照HDPE与尼龙－6共混材料结构与力学性能的研究

研究了紫外线辐照ＨＤＰＥ与ＰＡ６共混材料的微观形态、结晶结构、熔融行为及力学性能。ＳＥＭ、ＷＡＸＤ、ＤＳＣ结果表明，随紫外线辐照时间的增加，共混物中ＰＡ６的粒径减小，与基体作用加强，ＨＤＰＥ晶面间距增大，熔点、结晶度降低，熔程变窄。力学性能测试结果表明，紫外线辐照能明显提高共混材料（ｕＨＤＰＥ／ＰＡ６：９０／１０）的拉伸强度、断裂伸长率、拉伸断裂能和冲击强度。当辐照时间超过１４４ｈ由于ＨＤＰＥ热稳定性明显降低，共混过程中ＨＤＰＥ热降解严重，共混物的韧性突降。     

Influence of reactive compatibilizers on the rheometrical and mechanical properties of PA6/LDPE and PA6/HDPE blends

In this work, the influence of reactive compatibilizers on the rheometrical and mechanical properties of polyamide 6/low density polyethylene (PA6/LDPE) and polyamide 6/high density polyethylene (PA6/HDPE) blends was investigated. Polyethylene grafted with maleic anhydride (PEgMA), polyethylene grafted with acrylic acid (PEgAA), and ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) were used as compatibilizers. The blends were characterized by torque rheometry, mechanical properties, and morphology. Rheometrical properties results show that PEgMA and PEgAA compatibilizers are more reactive with PA6 than EMA-GMA. Mechanical properties and scanning electron microscopy analysis results show that EMA-GMA compatibilizer is as effective as PEgMA and PEgAA for PA6/LDPE blend. For PA6/HDPE blend, PEgAA and EMA-GMA compatibilizers proved to be as effective as PEgMA. For PA6/HDPE blend compatibilized with PEgAA, an intriguing “web” or “bridge” like structure was observed.     

紫外线辐照HDPE与尼龙－6相容性的研究

采用ＩＲ、ＳＥＭ、ＤＳＣ和拉伸应力－应变曲线研究了紫外线辐照ＨＤＰＥ／ＰＡ６的相容性，结果表明，随紫外线辐照时间的增长，ＨＤＰＥ分子链上引入Ｃ＝Ｏ－Ｃ－Ｏ－等极性基团明显增加；ＰＡ６的粒径减小，与基体间界面作用加强；两组分玻璃化温度差（Ｔ_（ｇ，ＰＡ６）－Ｔ_（ｇ，ＨＤＰＥ））减小；共混物拉伸应力－应变曲线上出现屈服点及拉伸冷流塑性形变。当辐照时间达１４４ｈ后，由于ＨＤＰＥ热稳定性明显变差，共混物韧性突降，拉伸应力－应变曲线上未出现屈服点。     

Tensile dilatometry of injection-moulded HDPE/PA6 blends

In order to understand the mechanism of deformation of injection-moulded HDPE/PA6 (25 vol% /75 vol%) blends both with and without compatibilizer, the volume change has been monitored using tensile dilatometry. Dog-bone specimens were either directly moulded or cut from rectangular plaques. Both neat materials and their blends were tested. For the directly moulded dog-bone specimen, a pure shear yielding mechanism was observed for all materials tested, i.e. PA6, HDPE, and their blends in the same proportion as above. In the case of a deformable minor phase (HDPE), the dispersed phase appeared to bear its share of stress and the flow-induced orientation mimics the effect of interfacial modification. This was not the case of a rigid minor phase (glass beads) at the same concentration; the effect of surface treatment changed the mechanism of deformation from mixed mode cavitation shear yielding (45%) to almost pure shear yielding (85%). Machined specimens made of neat PA6 and HDPE deformed through pure shear yielding. The addition of 25 vol% HDPE to PA6 resulted in a mixed mode cavitation (55%)/shear yielding mechanism of deformation in the transverse direction, while in the longitudinal case, the mechanism which prevailed was almost pure shear yielding (80%). This can be attributed to the flow-induced orientation as above. When adding 10% (based on the weight of the dispersed phase) of an ionomer as a compatibilizer, the blend deformed via shear yielding (85%) and in the longitudinal direction both compatibilized and non-compatibilized blends display similar behaviour. Varying the specimen thickness by changing the mould cavity, led to a significant variation in the dilatational behaviour. Dilatometric behaviour is shown to be closely related to the morphology generated as a result of flow-induced orientation. The skin/core ratio, which is an indication of the proportion of the oriented dispersed phase to the non-oriented one, plays a key role in influencing the mechanism of deformation involved.     

正应力支配下混合顺序对PA6/HDPE/CNTs体系结构及性能的影响EI北大核心CSCD

利用自行研制的叶片式混炼装置,实现了正应力支配下聚合物复合体系的熔融共混。实验研究了混合顺序以及混合时间对高密度聚乙烯(HDPE)/尼龙6(PA6)/碳纳米管(CNTs)共混物的微观结构、流变特性、热性能及宏观力学性能的影响。结果表明:正应力支配作用能在短混合时间内实现PA6粒子和CNTs的均匀分散,分散效率高;相比于将HDPE,PA6,CNTs三者同时共混或者是先将PA6与CNTs混炼制成母料,再与HDPE共混这两种混合顺序,先将HDPE与CNTs混炼制成母料,再与PA6共混制得的共混物中分散相PA6粒径最小,分散更均匀,共混物的热性能以及力学性能更好。     

电子束辐照对HDPE/PA6共混体系的影响

通过电子束辐照的方法，在高密度聚乙烯（HDPE）分子链上引入含氧极性基团，增加了HDPE分子的极性，改善了HDPE与PA6的界面相容性，本文通过FT－IR，SEM，接触角、DSC等方法对电子束辐照HDPE／PA6体系的界面相互作用及其对共混体系结构与性能的影响进行了研究，结果表明，HDPE经电子束辐照后，在其分子链上引入了含氧极性基团，提高了HDPE的极性，增加了表面自由能，从而改善了其与PA6界面相容性，随着辐照剂量的增大，PA6分散相的粒径变小，在HDPE基体中的分散更均匀。     

POE-g-MAH反应性增容HDPE/PA6共混合金的热致形状记忆性能

采用乙烯-辛烯共聚物接枝马来酸酐(POE-g-MAH)作为高密度聚乙烯(HDPE)/尼龙6(PA6)共混体系的反应性增容剂,通过熔融挤出制备出固定相具有物理交联结构的热致形状记忆合金。研究了组分含量,拉伸比和形变回复温度对合金的形变回复率和回复速率的影响。结果表明,POE-g-MAH的添加显著提高了共混合金的形状记忆性能,当组分配比为80/20/10(HDPE/PA6/POE-g-MAH),形变回复温度为135℃,拉伸比为75%时,试样形变回复率达到96.5%。     

Processing and properties of bone-analogue biodegradable and bioinert polymeric composites

This paper summarizes the processing and properties of bone-analogue composites aimed to be used in temporary or permanent orthopaedic applications. The studied matrices were two biodegradable starch based blends (with ethylene-vinyl alcohol copolymer or with cellulose acetate) and three high density polyethylene (HDPE) grades. Composites of these materials with hydroxyapatite (HA—the main inorganic constituent of the human bone) were produced by extrusion compounding and subsequently injection moulded. A non-conventional injection moulding technique known as shear controlled orientation in injection moulding (SCORIM) was used deliberately to induce a strong anisotropic character to the processed composites. For the case of HDPE based composites, an alternative reinforcement system based on carbon fibres (C fibres) was also studied. For that, a special moulding technique that combines, in a single equipment, a compounding with an injection unit was used. Composites featuring a sandwich like structure were also produced by mono-sandwich injection moulding. These composites combine a HDPE/HA outer layer and HDPE/C fibre reinforced core. The aim is to produce composites with a mechanical behaviour matching that of human cortical bone and simultaneously a strong bioactive (bone-bonding) character. For all the cases, the mechanical performance of the produced composites was assessed and the structure developed investigated and related to the processing conditions. It was possible to produce, both biodegradable and bioinert matrix composites, with properties that might allow for their application in the orthopaedic field.