Monomer casting nylon-6-b-polyether amine copolymers: Synthesis and properties

MC nylon-6-b-polyether amine copolymers were prepared with macro-initiator based on amino-terminated polyether amine functionalized with isocyanate via in-situ polymerization. It was found that the introduction of polyether amine delayed the polymerization process of caprolactam by increasing apparent activation energy and pre-exponential factor, resulting in the decrease of molecular weight of nylon-6. The motion of molecular chain of the copolymers was easy because of the decreased hydrogen bonds and weakened inter-molecular forces. The physical entanglement of molecular chains of the copolymers was significant and strong which increased the entanglement density. Only the nylon-6 phase crystallized in the copolymers and the crystal grain size, spherulite size and crystallinity of the copolymers decreased. A small amount of γ crystal formed at high polyether amine content. The copolymers presented obvious strain hardening behavior in stress-strain curves and the loss factor dramatically increased while the glass transition temperature and storage module decreased. The fracture surface of the copolymers became rough and presented hairy structure, indicating that the toughening mechanism of the copolymers corresponded to the multi-layer crack extension mechanism.     

High performance LDPE/thermoplastic starch blends: a sustainable alternative to pure polyethylene

Thermoplastic starch (TPS), as opposed to dry starch, is capable of flow and hence when mixed with other synthetic polymers can behave in a manner similar to conventional polymer-polymer blends. This paper presents an approach to preparing polyethylene/thermoplastic starch blends with unique properties. A one-step combined twin-screw/single screw extrusion setup is used to carry out the melt-melt mixing of the components. Glycerol is used as the starch plasticizer and its content in the TPS is varied from 29 to 40%.Under the particular one-step processing conditions used it is possible to develop continuous TPS (highly interconnected) and co-continuous polymer/TPS blend extruded ribbon which possess a high elongation at break, modulus and strength in the machine direction. The PE/TPS (55:45) blend prepared with TPS containing 36% glycerol maintains 94% of the elongation at break and 76% of the modulus of polyethylene. At a composition level of 71:29 PE/TPS for the same glycerol content, the blend retains 96% of the elongation at break and 100% of the modulus of polyethylene. These excellent properties are achieved in the absence of any interfacial modifier and despite the high levels of immiscibility in the polar-nonpolar TPS-PE system. The 55:45 blend possesses a 100% continuous or fully interconnected TPS morphology, as measured by hydrolytic extraction. This highly continuous TPS configuration within the blend should enhance its potential for environmental biodegradation. The elongation at break in the cross direction of these materials, although lower than the machine direction properties, also demonstrates ductility at high TPS concentrations. At a glycerol content of 36% in the TPS, the blends demonstrate only very low levels of sensitivity to moisture. A high degree of transparency is maintained over the entire concentration range due to the similar refractive indices of PE and TPS and the virtual absence of interfacial microvoiding.Effective control of the glycerol content, TPS concentration and processing conditions can result in a wide variety of morphological structures including spherical, fiber-like, highly continuous and co-continuous morphologies. These various blend morphologies are shown to be the determining parameters with respect to the observed mechanical properties.This material has the added benefit of containing large quantities of a renewable resource and hence represents a more sustainable alternative to pure synthetic polymers.     

国内动态硫化技术产业化的探讨

根据国外动态硫化技术的发地趋势，结合国内科研情况．对ＴＰＶ推广应用的可能性进行了分析，并对今后的发展提出了建议。国内ＴＰＶ的主要应用市场是轿车及电线电缆行业。顶计２０００年，轿车行业对ＴＰＥ的需求量达３２５０ｔ／ａ。国内ＥＰＤＭ／ＰＰＴＰＶ工厂成本不超过１．７万元／ｔ．售价将远低于Ｓａｎｔｏｐｒｅｎｅ。     

热塑性淀粉加工过程的控制参数及塑化程度的表征方法

在介绍热塑性淀粉塑料加工原理的基础上,提出特殊机械能可以作为描述热塑性淀粉塑化过程的控制参数;并对表征热塑性淀粉塑化程度的各种方法进行了总结和评述。     

动态硫化EPDM/PP热塑性弹性体的研究进展

阐述了EPDM/PP共混型热塑性弹性体的发展历史、微观结构、性能、硫化体系、制备工艺、加工设备及研究展望。     

多糖类生物降解材料的研究进展

本文在参考二十八篇文献及专利报道的基础上详述了以多糖类天然高分子为原料的生物降解材料的研究发展。淀粉、纤维素、壳聚糖及其它多糖，是自然界中大量存在的天然高分子材料，来源丰富，价格低廉、且易被微生物分解。多糖类降解材料可用通用的加工方法和设备加工成型，产品性能优良，可完全生物降解，其开发和应用是解决目前世界范围内的塑料产生的污染问题的理想途径。     

热塑性聚合物/UP树脂混合体系的研究

采用本体聚合法合成具有一定转化率的热塑性聚合物TP ,并将其与不饱和聚酯 (UP)树脂混合 ,对所得混合树脂体系的流变性能、收缩性能、力学性能等进行了研究 ;利用动态力学方法分析了体系中热塑性聚合物与UP树脂的相容性 ,并对混合树脂体系进行了光学微观结构和红外光谱分析。结果表明 :TP与UP树脂间有一定的相容性 ,但并不完全相容 ;当UP树脂中加入TP 5份时 ,体系的粘度由 3Pa·s降为 2 5 5Pa·s ,收缩率由 1 77%降为1 45 % ;而加入 10份的TP ,树脂粘度降为 1 8Pa·s ,收缩率降为 1 3 9%。另外 ,体系的弯曲强度随TP加入量的提高而增加 ,但冲击强度的变化却呈先增加后降低的趋势。     

热塑型聚氨酯复合体系力学性能研究

采用压延机，在加工温度不高于１２０°Ｃ的条件下，成功地制备出热塑型聚氨酯弹性体（ＴＰＵ）与高氯酸铵、铝粉及增塑剂邻苯二甲酸二丁酯（ＤＢＰ）等组成的复合胶片，拉伸实验结果指出了所制备的热塑性弹性体复合体系具有良好的力学性能，完全达到或超过推进剂体系的要求指标。     

高聚合度PVC／TPU共混物的制备与研究

本文研究了采用高聚合度聚氯乙烯(PVC)和热塑性聚氨酯(TPU)为主体材料制备高聚合度PVC/TPU共混物的过程,讨论了高聚合度PVC/TPU并用比、填料、增塑剂、共混工艺等因素对高聚合度PVC/TPU共混物性能的影响。     

动态硫化工艺对EPDM/PP相态结构及力学性能的影响

采用透射电镜(TEM)研究二次硫化的加工工艺对EPDM/PP热塑性弹性体相态结构及力学性能的影响,研究发现,与传统的一次硫化的加工工艺相比,采用二次硫化加工工艺制备的EPDM/PP弹性体,硫化橡胶能以颗粒态均匀分散于PP的连续相中,其力学性能也较一次硫化制备的样品有较大提高。