酚酞型聚芳醚砜的溶解度参数测定

酚酞型聚芳醚砜(PES-C)是一种新型工程塑料,用它制作超滤膜材料引起人们的重视,因此测定PES-C的溶解度参数对研究其溶液性质和制膜工艺有较大意义。本文以氯仿为溶剂,甲醇和正己烷为沉淀剂,用浊度法测定了PES-C的溶解度参数。结果表明,该法是测定PES-C溶解度参数的一种简便有效的方法。测得PES-C在20℃时的溶解度参数δ为20.19(J/mL)~(1/2)。     

酚酞型聚芳醚砜共聚物的合成与表征

研究了酚酞(PP),4,4'-二羟基二苯硫醚(Bis—T),4,4'-二氯二苯砜(DCDPS)三元共聚物(PP/Bis-T)PES的聚合反应过程,热性能及部分力学性能。适宜的聚合温度为185～195℃。(PP/Bis—T)PES属于均相无规共聚物。共聚物具有良好的热稳定性、良好的机械性能。     

酚酞基聚芳醚砜改性双酚A型氰酸酯预聚体的制备及性能研究

将酚酞基聚芳醚砜（PES-C）与双酚A型氰酸酯（BCE）共混,在一定的条件下使氰酸酯预聚,得到酚酞基聚芳醚砜与双酚A型氰酸酯共混改性预聚体系,借助FT-IR和DSC确定了固化工艺,并用扫描电镜（SEM）对预聚体及其固化物进行表征,测试了改性体系的冲击强度和对铝合金的粘接强度。结果表明,PES-C对CE起到了明显的增韧改性的作用,改性体系固化物具有较好的介电性能,在常温到230℃范围内粘接剪切性能优异（均大于20MPa）。该改性体系可用作一种新型耐高温结构胶黏剂的主体树脂。     

酚酞型聚芳醚砜改性氰酸酯树脂性能

氰酸酯树脂是一种黏接强度高、介电性能优异的耐高温树脂,但因韧性较差严重限制了氰酸酯树脂的应用,采用双酚E型氰酸酯(BEDCy)树脂作为基体树脂,酚酞型聚芳醚砜(PES-C)作为增韧剂,通过加热共混得到了BEDCy/PES-C树脂。通过拉力机、动态力学热分析、热重(TG)分析、X射线光电子能谱、阻抗分析和扫描电子显微镜(SEM)测试了BEDCy/PES-C树脂对铝材的黏接强度、模量、耐热性、介电性能、微观结构和形貌的影响。结果表明,PES-C对BEDCy树脂的增韧效果显著,以剪切性能为例,BEDCy树脂在常温下剪切强度由最初的19.9 MPa提升至30.4 MPa,相比纯BEDCy树脂提高了52.8%,230℃下剪切强度提高了36.7%,此时,SEM下也能观察到明显的沟壑状增韧条纹。TG分析测试表明,少量PES-C (<40%)的加入对耐热性能影响并不明显,失重率5%时温度基本保持在418℃。BEDCy/PES-C的介电性能也明显提高,当PES-C质量分数为20%时,10.1 GHz下的介电常数为2.41,介电损耗为0.010 6。     

酚酞聚芳醚砜/灌流硅胶微球复合材料的耐热性能研究

利用热重分析仪对PES-C/PSM复合材料的耐热性能进行分析,并以Kissinger法研究其热分解动力学,计算热分解表观活化能Ea。结果表明,在空气氛下复合材料的热分解温度随PSM含量的增大而升高,且当PSM的含量提高至1.0%,复合材料的热分解结束温度提高了41.29℃。复合材料的表观热降解活化能随PSM含量的增加而增大,与纯PES-C(Ea_(PES-C)=241 kJ/mol)相比,当PSM含量为1.0%时,PES-C/PSM复合材料的活化能为264.76 kJ/mol,较纯PES-C提高了9.86%。     

聚四氟乙烯填充酚酞聚芳醚酮的研究

通过对PEK—C与PTFE共混物的模压成型材料的研究,表明PEK—C树脂加入10％～20％PTFE填充改性后,不仅很大程度上保持了PEK—C的良好的机械性能和热性能,而且其摩擦性能得到了明显地改善,制备了一类新型无油润滑的耐高温低摩擦材料。     

环氧端基酚酞聚芳醚腈改性环氧树脂胶粘剂性能的研究

通过差示扫描量热 (DSC)、热解重量分析 (TGA)和粘接强度的测定 ,对环氧端基酚酞聚芳醚腈改性的环氧树脂胶粘剂的性能进行了研究     

酚酞基聚芳醚酮改性环氧树脂结构胶膜的研制

以酚酞基聚芳醚酮(PEK-C)为主增韧剂、环氧基丁腈橡胶为辅助增韧剂、芳香胺为固化剂、E-51(双酚A型环氧树脂)为主体树脂、F-44(酚醛型环氧树脂)和AG-80(四官能团环氧树脂)为改性树脂,制备出一种改性EP结构胶膜。研究结果表明:当w(PEK-C)=45%~50%、w(环氧基丁腈橡胶)=12%(均相对于EP结构胶膜质量而言)时,EP结构胶膜的玻璃化转变温度(Tg)为179.8℃、滚筒剥离强度为123.60 N·mm/mm,并且其粘接性能、耐热性和耐久性俱佳。     

抗辐照酚酞聚芳醚酮基自润滑复合材料的研制

采用二硫化钼、石墨、碳纤维和氟化镧研制了一种抗辐照的酚酞聚芳醚酮基自润滑复合材料。介绍了此材料的制备工艺和性能,研究了几种添加剂的配比对复合材料的影响。结果表明,在酚酞聚芳醚酮中添加二硫化钼和石墨可明显改善材料的摩擦磨损性能,加入碳纤维和氟化镧不仅可提高复合材料的机械强度,而且还使摩擦磨损性能在一定程度上得到改善。加入上述添加剂均可提高复合材料的抗辐照性。     

PE,EVA及LDPE／EVA共混物辐照特性的研究

本文在对乙烯－醋酸乙烯共聚物（ＥＶＡ）和聚乙烯（ＰＥ），低密度聚乙烯（ＬＤＰＥ）、线性低密度聚乙烯（ＬＬＤＰＥ）及高密度聚乙烯（ＨＤＰＥ）在＾６０Ｃｏγ射线辐照前后的性能进行比较的基础上，着重研究了ＬＤＰＥ／ＥＶＡ共混物在＾６０Ｃｏγ射线辐照前后的拉伸性能和交联度的变化，以及ＥＶＡ添加量、ＶＡ含量及熔体流动速率（ＭＦＲ）对这些变化的影响。     

PE/PVC共混物与PE界面黏结性能研究

为改善聚氯乙烯(PVC)和聚乙烯(PE)界面黏结性能,制备了一系列PE/PVC共混物及其与PE的黏结材料,探究了原料比例和成型温度对(PE/PVC)/PE界面黏结性能的影响。结果表明,PE/PVC共混物为不相容体系。共混物中随着PE含量升高,体系拉伸强度增大,断裂伸长率升高。(PE/PVC)/PE材料中,随着PE/PVC共混物中PVC含量升高,PE/PVC与PE的界面黏结强度先升高后降低。成型温度升高,界面黏结性能提高。在PE/PVC比例为60/40、黏结温度为100℃时,PE/PVC共混物与PE的界面黏结强度最大,可与共混物拉伸强度接近。     

Environmentally Degradable Blends of Low Density Polyethylene (LDPE) and Partially Carboxymethylated Starch (PCMS)

Abstract

Sodium - salt of partially carboxymethylated starch (Na-PCMS) with degree of substitution (DS) 0.21 and 0.58 was synthesized by etherification of starch. These starch ethers and low density polyethylene (LDPE) were mixed with and without poly(vinylacetate) (PVAc) in various proportions using Brabender mixer. FTIR confirmed the etherification reaction of starch and blending. Positive changes in the mechanical properties as a function of blending, and environmental degradation have been observed. Addition of 5 wt% PVAc improves the blend quality. Samples were exposed to direct sunlight for one month and environmental degradation was measured in terms of change in tensile strength and per cent elongation.     

Synthesis of amphiphilic graft copolymer with hydrophilic poly(acrylic acid) backbone and hydrophobic polystyrene side chains

A series of well-defined amphiphilic graft copolymers consisting hydrophilic poly(acrylic acid) backbones and hydrophobic polystyrene side chains were synthesized by successive atom transfer radical polymerization (ATRP) followed by hydrolysis of poly(methoxymethyl acrylate) (PMOMA) backbone. Grafting-from strategy was employed for the synthesis of graft copolymers with narrow molecular weight distribution. Hydrophobic side chains were connected to the backbone through stable C-C bonds. The backbone can be easily hydrolyzed with HCl without affecting hydrophobic side chains. This family of amphiphilic graft copolymers can form stable micelles in water. The critical micelle concentration was determined by fluorescence spectroscopy. The micellar morphologies and sizes were studied using transmission electron microscopy (TEM) and dynamic light scattering (DLS). The sizes of micelles were dependent on ionic strength, pH value and preparation conditions.     

Morphology and Properties of Deoiled Cake (DOC) Isolated Mixed Proteins and Low-Density Polyethylene Blends

Proteins were isolated from deoiled cakes (DOC) of soybean, castor and rapeseed. The isolated proteins were then blended with LDPE in different wt. ratios, using PEG₄₀₀ as a plasticizer. The morphology of the blends was evaluated by using a scanning electron microscope (SEM). Homogeneous blends were obtained and analyzed for various mechanical properties such as tensile strength, impact strength, hardness and % elongation and compared with properties of plastic sheets prepared from mixture of pure proteins. Results revealed that protein composition and amount of LDPE in proteins and LDPE blend, affects the mechanical properties of the plastic compositions considerably.     

接枝改性淀粉作为LLDPE／淀粉共混体系增容剂的研究

采用接枝改性淀粉作为LLDPE/淀粉共混体系增容剂,对其单体作用和与接枝改性PE配合作用的增容效果进行了研究,发现配合作用增容效果比较明显,体系拉伸强度可达9.77MPa,伸长率为128％,并在此基础上进一步考察了偶联淀粉与LLDPE共混的效果。     

mPE弹性体/PP共混物的流变行为与力学性能

用茂金属聚乙烯弹性体（mPE)代替传统的弹性体,对聚丙烯（PP）进行增韧改性,绘制了不同配比mPE/PP共混物熔体的流变曲线,讨论了共混物的组成,切应力和剪切速率以及温度对熔体流变行为,熔体粘度的影响。测定了共混物熔全的非牛顿指数,熔体质量流动速率及力学性能,为mPE共混改性PP提供了理论依据。结果表明,mPE适用于PP的增韧改性,增韧效果取决于共混物中mPE的用量,当mPE质量分数达到25%-40%时,共混材料既有较高的拉伸强度和韧性,又有较好的加工性能,mPE/PP共混物熔体的假塑性流动随mPE用量的增加向更高切应力或更高剪切速率方向移动。     

LDPE／EVA共混物挤出工艺与拉伸性能研究

研究了5种EVA添加量、VA含量和MFR对挤出LDPE/EVA共混物的挤出机各段温度、挤出机螺杆扭矩及拉伸性能的影响。     

Crystallization Behavior of the Blends of Isotactic Polypropylene and Ethylene-Propylene Blocky Copolymers

Two ethylene-propylene copolymer fractions (EP90 and EP120) were separated from a polypropylene in-reactor alloy by extraction with n-octane at different temperatures. ¹³C-NMR shows that these two fractions have a blocky structure and WAXD reveals that both ethylene and propylene sequences in these two fractions are crystallizable. However, EP90 has higher propylene content and the average length of propylene sequences is longer. These two fractions were blended with isotactic polypropylene (PP) at various proportions, respectively, and crystallization behavior and morphology of the blends were investigated. It is found that both EP90 and EP120 are partially compatible with PP. The phase-separated domains have a nucleation effect on crystallization of PP, leading to increase in crystallization temperature and crystallinity of PP in the blends. EP90 and EP120 also affect the relative content of β crystals in an irregular way. The number of EP90-rich domains in PP/EP90 blends is larger than that of EP120-rich domains in PP/EP120 blends, but the size of EP90-rich domains is smaller, indicating that EP90 has better compatibility with PP than EP120. Spherulites are formed in all the blends. The data were analyzed with Hoffman-Lauritzen theory of crystallization regime and the free energy of the folding surface (σ_e) was derived. Addition of EP90 and EP120 has little effect on the transition temperature from regime II to regime III. The value of σ_e for the PP/EP90 blends is similar to that of neat PP, but σ_e of the PP/EP120 blends is a little higher than that of neat PP.     

聚丙烯/聚乙烯共混物环状型坯挤出膨胀和垂伸的研究

利用双螺杆挤出机将聚丙烯分别与不同熔体流动速率的聚乙烯进行共混,通过环状型坯挤出,研究了共混物的型坯膨胀和垂伸情况。结果表明,聚丙烯与较高熔体流动速率的聚乙烯共混后,其型坯直径膨胀的变化范围较宽,垂伸较明显。