TPS/EVA共混物的性能研究

探讨了EVA、甘油的含量和润滑剂对TPS/EVA共混体系的力学性能、熔融流动性以及耐水性的影响。     

EVOH／PE-HD共混相容性研究

使用三种功能化改性的聚乙烯作为相容剂改善EVOH／PE-HD共混体系的相容性，研究了共混体系的热性能和力学性能。SEM表明，相容共混体系中形成了高度分散和牢固的界面结合，二甲苯萃取实验和IR分析证实了相容性的改善来自于EVOH与相容剂之间的化学反应。相容共混体系中EVOH作为分散相时其结晶温度明显降低，结晶速度放慢；共混物中两组分的结晶熔点均低于纯组分。这些均可归因于体系更好的相容性以及强烈的界面作用。相容共混体系的力学性能较之简单共混体系得到明显改善，EVOH为分散相时拉伸强度提高幅度较大(50％)，而在PE-HD为分散相时缺口冲击强度的增幅达到30％。     

热塑性淀粉/纤维共混物性能的研究

用甘油作为塑化剂，将糊化淀粉和溶胀纤维按不同配比进行熔融共混来制备完全可生物降解塑料。实验探讨了纤维质量分数对共混体系力学性能、耐水性及热性能的影响。扫描电镜显示了纤维较好地分散在热塑性淀粉(TPS)中，纤维和淀粉结合良好。纤维质量分数对共混体系力学性能影响的研究显示，纤维的加入可以明显地改善体系的力学性能。随着纤维质量分数由0提高到20％，共混体系的拉伸强度达到15．5MPa，杨氏模量达到81．4MPa；伸长率从104％降到7％。同时加入纤维后共混体系的耐水性明显提高。     

乙酰化淀粉/聚己内酯共混物的制备和性能研究

分别采用淀粉(TPS)、乙酰化淀粉(TPAS)与聚己内酯(PCL)进行熔融共混，制备了可生物降解的塑料，探讨了淀粉乙酰化改性后对共混物力学性能、耐水性、熔融流动性、相容性及生物降解性的影响。共混物的拉伸强度均随PCL用量的增加而增大，TPAS／PCL体系的拉伸强度低于TPS／PCL体系，而断裂伸长率高于TPS／PCL体系。PCL可以明显改善淀粉基材料的耐水性，淀粉乙酰化后共混体系的相容性及熔体流动性得到一定的改善，生物降解性略微下降。     

热塑性淀粉增韧改性聚酰胺6的研究

将甘油增塑玉米淀粉制得的热塑性淀粉（TPS）与聚酰胺6（PA6）进行熔融共混,制备PA6/TPS共混物,研究不同含量的甘油和TPS对PA6/TPS共混物性能的影响,并探讨TPS增韧PA6的机理。采用万能试验机、溶体流动速率仪和扫描电子显微镜对改性PA6进行表征。结果表明,加入TPS后,共混物的冲击强度和拉伸模量有所提高,而拉伸强度和熔体流动速率略有下降,表明TPS对PA6起到了有机刚性粒子增韧的作用;TPS对PA6的增韧机理主要是界面脱黏、空化作用;甘油含量对TPS改性PA6的韧性影响显著,甘油含量为25 %的TPS添加量为25 %时,其增韧效果最好,冲击强度比PA6提高了63 %。     

ASA／PVC共混改性技术在PVC彩色共挤型材加工中应用研究

本文概述了ASA／PVC共混改性彩色共挤型材的制备工艺，分析讨论了不同配比共混体系对共挤加工性能、材料力学性能以及材料耐候性能的影响。     

增容剂含量对PP／EVOH共混物流变性能的影响

采用熔融共混法制备了聚丙烯／乙烯-乙烯醇共聚物（PP／EVOH）共混物,利用毛细管流变仪对共混物的流变行为进行了研究。结果表明：PP／EVOH共混物为假塑性流体,呈现出切力变稀的现象。马来酸酐接枝乙烯-辛烯共聚物（POE-g-MAH）的加入增大了PP／EVOH共混物的粘流活化能,说明共混物对温度的敏感性较强。     

PE-HD／PA6／EVOH阻透容器成型工艺与性能研究

将高密度聚乙烯（阻HD）、聚酰胺6（PA6）与乙烯-乙烯醇共聚物（EVOH）的复配体和相容剂初混合后，通过挤出机熔融共混、中空吹塑制得阻透容器。考察了树脂及共混物的流变性能，研究了相容剂用量、阻透树脂用量和成型工艺条件对容器阻透性能的影响。利用扫描电镜（SEM）观察了瓶壁的层状结构。实验结果表明，PA6／EVOH复配体增加了阻透树脂的熔体黏度，提高了层状共混工艺的稳定性。与PE-HD／PA6二元共混容器相比。PE-HD／PA6／EVOH三元共混容器所需相容剂更少。当阻透树脂用量为15～18份、相容剂用量为2～3份、加工温度在225～230℃之间、螺杆转速控制在30r／min左右、停留时间在3min时，PE-HD／PA6／EVOH共混容器的阻透性能得到明显提高。     

淀粉基生物降解塑料制备研究进展

简介了热塑性淀粉(TPS)的性质,分别总结了TPS/聚乳酸(PLA)共混物、TPS/聚己内酯(PCL)共混物、TPS/醇酸共聚酯共混物、TPS/聚碳酸亚丙酯(PPC)共混物、TPS/聚乙烯醇(PVA)共混物等热塑性淀粉与合成聚合物共混体系研究现状,以及TPS与天然大分子的共混体系研究现状,并提出了淀粉基生物降解塑料目前存在的问题及今后发展方向。     

TPS/PVA共混物的热降解行为

以热塑性木薯淀粉(TPS)为研究对象,甘油或甲酰胺/尿素为增塑剂,通过熔融共混法制备TPS/聚乙烯醇(PVA)共混物,利用热重分析仪研究增塑剂种类、用量及PVA对TPS热降解行为的影响。结果表明:添加甘油的TPS热降解温度高于添加甲酰胺/尿素复配增塑剂;随着甘油用量的增加,TPS热降解温度降低;添加PVA后,TPS热降解温度降低,且随着PVA用量的增加而降低;TPS热降解过程分为3个阶段,TPS/PVA共混物的热降解分为4个阶段;随着升温速率的增加,TPS的热降解温度升高;采用Kissinger研究了TPS/PVA共混物的热降解动力学,PVA的加入降低了TPS的热降解活化能。     

Effect of Thermoplastic Starch and Photocrosslinking on the Properties and Morphology of Electrospun Poly(ethylene-co-vinyl alcohol) Mats

Nonwoven fibrous mats of poly(ethylene-co-vinyl alcohol) (EVOH) and thermoplastic starch (TPS) blends were successfully prepared through the electrospinning technique using a mixed solvent system of isopropyl alcohol and water. The influence of TPS on the morphology and structure of the fibrous mats was investigated using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy. The addition of TPS to EVOH resulted in beaded electrospun fibers. The SEM images revealed decreasing average width of the blend fibers and increasing quantity of beads with an increased TPS content. EVOH/TPS fibers mats irradiated under ultraviolet light using sodium benzoate as a photosensitizer were also prepared. The size and number of beads were diminished in the photocrosslinked EVOH/TPS fiber mats. The as-spun and crosslinked EVOH/TPS fiber mats exhibit a superior fluid uptake ability (with 20 wt% of TPS) and superior barrier properties (with 20 and 40 wt% of TPS) in comparison to those observed in neat electrospun EVOH mats. These properties are of particular interest for use in dressing materials for the medical industry and for use in multilayer plastic fuel tanks for the automotive industry, respectively. POLYM. ENG. SCI., 60:474–480, 2020. © 2019 Society of Plastics Engineers     

PP/POE-g-MAH/EVOH共混物的流变性能研究

采用熔融共混法制备了PP/POE-g-MAH/EVOH共混物,利用毛细管流变仪对共混物的流变行为进行了研究。结果表明:PP/POE-g-MAH/EVOH共混物为假塑性流体,其表观黏度随着EVOH含量的增加先升高后降低,当EVOH含量为20%时,表观黏度达到最大值。EVOH的加入增大了PP/POE-g-MAH/EVOH共混物的黏流活化能,说明共混物对温度的敏感性较强。     

原位增容PA6/POE/EVOH共混物的流变性能研究

采用熔融共混法制备了聚酰胺6/乙烯-1-辛烯共聚物/乙烯-乙烯醇共聚物(PA6/POE/EVOH)共混物,利用毛细管流变仪对共混物的流变行为进行了研究。结果表明:PA6/POE/EVOH共混物为假塑性流体,呈现出切力变稀的现象;EVOH的加入增大了PA6/POE/EVOH共混物的表观黏度和黏流活化能,说明共混物对温度的依赖性较强。     

Fabrication and characterisation of thermoplastic starch/poly(butylene succinate) blends with maleated poly(butylene succinate) as compatibiliser

Thermoplastic starch/poly(butylene succinate) (TPS/PBS), an entirely biodegradable polymer blend, was prepared by a two-step extrusion method. Maleic anhydride grafted PBS (rPBS) was successfully synthesised as an interfacial compatibiliser. The miscibility, morphology, thermal behaviour and mechanical properties of the TPS/PBS blends were investigated. The results demonstrated that the strength and elongation at break of TPS/PBS blends were greatly increased with the addition of rPBS in PBS blends due to improved interfacial miscibility. Better distribution and smaller phase domain were observed in the blends with higher content of compatibilisers. The water resistance was also enhanced by incorporation of rPBS. It was indicated that compatibilised TPS/PBS blends possessed a combination of good biodegradability, improved strength and high water resistance. TPS/PBS blend was expected to serve as a promising packing material.     

Interface evaluation in the ternary blends of HDPE/PA-6/EVOH

In this work, a quantitative evaluation on interface situation in HDPE/PA-6/EVOH ternary blends is presented. For this purpose, binary and ternary blends based on HDPE as continuous phase and PA-6 and EVOH as minor components with different weight ratios were prepared. The morphology of the blends was studied by SEM and their mechanical properties were measured. Then, through a theoretical/experimental approach, the tensile characteristics of HDPE/PA-6/EVOH ternary blends are discussed. The interface situation in the prepared blends is probed in such a manner that phenomenological models are successfully extended to the case of ternary blends and their parameters are obtained using available predictive schemes. In addition, the stress–strain curves of all prepared binary and ternary blends comprising different PA-6 to EVOH weight ratios in the minority phase are taken into account to study the yielding and toughening phenomena followed by quantitative evaluation of interfacial adhesion. The results provided support for the fact that the yielding behavior of prepared ternary blends is dependent on the minor component fraction possibly due to the formation of voids at the interface of polymers.     

热塑性淀粉／聚己内酯共混物的制备和性能的初步研究

利用热塑性淀粉（TPS）与聚己内酯（PCL）熔融共混并挤出可用来制备完全可生物降解的塑料，研究表明，组分PCL以及增塑剂水和甘油的含量对体系的力学性能和耐水性有显著的影响。     

不同淀粉类型TPS/PBS共混体系的形貌与黏弹行为

引言自20世纪70年代以来,随着环保意识的不断增强以及石油资源的日益枯竭,生物质基高分子材料的研究价值日益凸显[1-3]。其中淀粉由于来源广泛、价格低廉以及完全生物降解引起了人们的广泛关注[4-5]。     

苹果酸对聚乳酸/热塑性淀粉共混物结构与性能的影响

将天然淀粉用甘油改性后制得了热塑性淀粉(TPS),再通过熔融共混法制备了聚乳酸(PLA)/TPS共混物。通过SEM、TG、DSC分析和拉伸性能、吸水性能、流变性能测试,研究了苹果酸对TPS和PLA/TPS共混物结构和性能的影响。结果表明:苹果酸能促进淀粉酸解,使TPS分散相尺寸减小,在PLA基体中的分布更加均匀;苹果酸能提高PLA/TPS共混物的拉伸性能;苹果酸对PLA/TPS共混物的玻璃化转变温度、熔融温度及冷结晶温度影响较小;少量的苹果酸可降低PLA/TPS共混物的吸水率。     

Tailoring morphology to improve the gas‐barrier properties of thermoplastic polyurethane/ethylene‐vinyl alcohol blends

The morphology and helium‐barrier properties of thermoplastic polyurethane (TPU)/ethylene‐vinyl alcohol (EVOH) blends with and without dicumyl peroxide (DCP) were investigated by melting blending. A lamellar dispersion of EVOH with good helium‐barrier properties was observed in the TPU matrix with DCP. The evolution of the morphology of the blends is mainly related to the variation of the viscosity ratio between the dispersed phase and the matrix phase. Compared with pure TPU, lamellar morphology increased the helium‐barrier properties of the TPU/EVOH (60/40) blend by as much as 10‐fold. We also explored the effects of composition, DCP content, and blending sequence on the morphology and helium‐barrier properties of the TPU/EVOH blends. The morphology of the blends ranged from a droplet‐matrix to a lamellar structure. We determined the optimum amount of DCP to improve the helium barrier of the blends. The helium‐barrier properties of the blends prepared by direct blending were superior to those of the blends prepared by two‐segment blending, and the blends prepared by direct blending exhibited a well‐developed lamellar morphology. We compared the permeability of the samples with the theoretical results to explain the relationship between morphology and helium‐barrier properties. POLYM. ENG. SCI., 56:922–931, 2016. © 2016 Society of Plastics Engineers