Maleated High Density Polyethylene Compatibilized High Density Polyethylene/Hydroxyapatite Composites for Biomedical Applications: Properties and Characterization

The study investigated the use of maleated high density polyethylene (mHDPE) as a compatibilizer in high density polyethylene/hydroxyapatite (HDPE/HA) composites for biomedical applications. The addition of HA increased the strength and stiffness of HDPE/HA composites while the use of mHDPE in HDPE/HA composites improved its elongation at break values. The SEM images revealed that the addition of mHDPE has induced the formation of HDPE fibrils in mHDPE/HA composites. The size of apatite layer increased with simulated body fluid (SBF) immersion time and the formation of apatite layers on the surface of composites indicates excellent biocompatibility properties.     

高密度聚乙烯催化剂的制备和催化性能

概述了高密度聚乙烯在国民经济中的广泛用途，以及聚乙烯工业的催化剂研究领域的最新进展。     

硅烷接枝HDPE/纳米SiO_2复合材料的制备与性能

将经表面处理后的纳米SiO2和硅烷接枝高密度聚乙烯(HDPE)熔融共混制得硅烷接枝HDPE/纳米SiO2复合材料,并对其结晶行为、力学性能及热性能进行了研究。结果表明:与HDPE相比,硅烷接枝HDPE/纳米SiO2复合材料的结晶度降低约17%;在纳米粒子含量为6%时,热分解温度提高了15℃;在纳米粒子含量为10%时,体系的拉伸强度提高了25%。     

Preparation and Performance of High-Barrier Low Density Polyethylene/Organic Montmorillonite Nanocomposite

Montmorillonite (MMT) was first modified with dodecyl dimethylbenzyl ammonium (DDA) salt and octadecyl trimethyl ammonium (OTA) salt. Then low density polyethylene (LDPE)/organic montmorillonite (OMMT) nanocomposites were prepared by twin-screw extruder and hot-press. Transmission electron microscopy (TEM) results showed that OMMT layers were homogeneously intercalated into the LDPE matrix. In terms of MMT, the modification effect of OTA is superior to that of DDA. CO₂ and O₂ barrier properties of nanocomposites were increased by 7 times and 4 times with 0.5 wt.% OTA-MMT loading, respectively. At 2 wt% OTA-MMT loading, water vapor permeability of LDPE has also decreased about 2.5 times. Compared with pure PE film, 49.5% and 178% improvement of tensile strength of nanocomposites films were obtained by addition of only 4 wt.% DDA-MMT and OTA-MMT, respectively. In addition, with only 0.5 wt.% OMMT loading, the onset degradation temperature of nanocomposites increases by 23°C and 26°C for LDPE/DDA-MMT and LDPE/OTA-MMT, respectively.     

Preparation and Characterization of Potato Starch Based Low Density Polyethylene/Low Density Polyethylene Grafted Maleic Anhydride Biodegradable Polymer Composite

Polysaccharide-filled plastics have attracted immense interest from research scientists as a means to develop a biodisintegrable polymer. The objective of the present study is to develop a biodisintegrable polymer composite using potato starch, which may be a step toward an alternative user friendly polymer composite. Keeping in mind the compatibility issue between potato starch and polyethylene, we used a base material with a polar group in its low density polyethylene (LDPE) backbone. Polymer composite sheets with a combination of potato starch, LDPE, and LDPE grafted maleic anhydride (LDPE-g-mA) were prepared. The LDPE and LDPE-g-mA were used in equal amounts and as a base material. The starch contents varied between 0 and 30%. The composites so prepared were tested for their thermal and mechanical properties. The results show that the thermal stability and melting temperature of these composites did not change significantly with various combinations of potato starch. The mechanical testing results show that tensile strength of material could be maintained at up to 15% mixing of potato starch in composites, and at up to 5% mixing of potato starch the percentage elongation was intact.     

高密度聚乙烯／蒙脱土纳米复合材料的制备与性能研究

采用马来酸酐接枝乙烯醋酸乙烯酯（EVA-g-MAH）和马来酸酐接枝低密度聚乙烯（PE-LD-g-MAH）为相容剂，制备了高密度聚乙烯傣脱土（PE-HD／MMT）纳米复合材料。用X射线衍射和扫描电镜对有机蒙脱土和PE-HD／MMT复合材料的结构进行了表征，研究了蒙脱土和相容剂含量对制备的纳米复合材料力学性能及热性能的影响。结果表明，相容剂的加入有利于插层。MMT在复合材料中呈纳米级分散。其层间距可由2．10nm增大至3．85nm。MMT含量为3％（质量分数，下同）、EVA-g-MAH含量为15％时，复合材料的综合力学性能最好，冲击强度和拉伸强度分别较PE-HD提高43．7％和5.8％。     

黑山膨润土钠化工艺研究

以黑山天然膨润土为原料,采用阳离子交换树脂交换的方法对天然膨润土进行钠化改型,通过正交试验确定了最佳条件。该方法具有不引入阴离子或沉淀物、分离容易等优点,大大减少了后处理步骤。制备出稳定的钠基蒙脱石悬浮液,干燥后产品的阳离子交换容量是127.88 mmol/100 g,吸蓝量为42.35 g/100 g,蒙脱石纯度达到了95.81%。XRD衍射分析表明产品达到高品质钠基蒙脱石的要求,为其深层次的加工应用打下良好的基础。     

高密度聚乙烯/硅酸钙复合材料的制备与性能研究

采用双螺杆挤出机制备了不同含量高密度聚乙烯(PE–HD)/硅酸钙(Ca Si O3)复合材料,并采用马来酸酐接枝聚乙烯作为相容剂对该复合材料进行改性,研究了相容剂含量对复合材料力学性能的影响。结果表明,随着相容剂含量的增加,复合材料的力学性能先增加后保持不变,综合考虑,相容剂含量为10份时,对复合材料的力学性能改性效果最佳。然后以此相容剂含量为基准,研究了Ca Si O3含量对复合材料力学性能和阻燃性能的影响。结果显示,随着Ca Si O3含量的增加,复合材料的冲击强度增加,拉伸强度先下降后上升,氧指数略有增加,垂直燃烧性能变化不大。这表明Ca Si O3的填充对PE–HD具有较好的增韧效果,对阻燃性能也有一定提高。     

低密度聚乙烯/石墨烯纳米复合材料非等温结晶动力学

采用差示扫描量热仪研究了不同石墨烯(GP)含量的低密度聚乙烯(PE–LD)纳米复合材料在不同降温速率下的非等温结晶行为。结果表明,不同含量GP填料的加入均导致PE–LD结晶温度提高,表明GP填料对PE–LD基体起到异相成核作用;莫志深法能很好地描述纳米复合材料的动态结晶行为。动力学数据显示,当GP质量分数为0.5%和2%时,PE–LD复合材料的整体结晶速率、活化能、成核常数和生长晶面的表面自由能均比纯PE–LD低,而含量为5%时其值均比纯PE–LD高,因此适量的GP有利于PE–LD的结晶。由成核常数、表面自由能值可看出低含量GP促进PE–LD晶粒的二次成核、生长,而高含量GP则抑制晶粒二次成核、生长。     

高密度聚乙烯增韧改性的研究进展

系统地介绍了高密度聚乙烯(HDPE)的增韧改性技术和工艺,并分析了HDPE增韧技术与应用中的问题。     

Thermal Behavior and Degradation Kinetics of Compatibilized Metallocene-Linear Low Density Polyethylene/Nanoclay Nanocomposites

Morphology, thermal degradation and kinetics of metallocene-linear-low-density polyethylene (m-LLDPE)/m-LLDPE-graft-maleic anhydride (m-LLDPE-g-MA)/nanoclay nanocomposites were compared with m-LLDPE/nanoclay, m-LLDPE-g-MA/nanoclay and m-LLDPE/m-LLDPE-g-MA systems. X-ray diffraction measurements revealed intercalated and “highly intercalated” morphologies for the nanocomposites. Thermogravimetric analysis demonstrated that although thermal degradation of m-LLDPE systems were delayed upon the inclusion of nanoclay in air, an inverse effect was perceived for the nanoclay under inert atmosphere. This conclusion was supported by kinetic analysis in terms of reaction order and activation energy. The results obtained from kinetics models also put forward the contribution of m-LLDPE-g-MA, as a compatibilizer, to the thermal stability enhancement through inter-molecular cross-linking augmentation.     

聚乙烯原料对高密度聚乙烯土工膜性能的影响

本实验采用吹塑成型工艺,以不同牌号的聚乙烯(PE)树脂为原料生产2 mm厚度双光面高密度聚乙烯(HDPE)土工膜,研究PE原料对HDPE土工膜性能的影响。结果表明:中密度聚乙烯(MDPE)土工膜综合性能优异,主要是由其特有的分子结构(如分子量分布双峰性、α烯烃长支链)所决定的;不同PE原料氧化诱导时间不同,可通过调节含抗氧剂色母料(或抗氧剂)的含量,使HDPE土工膜氧化诱导时间达到要求;HDPE土工膜在焊接时应根据PE材质的不同而选择不同的焊接条件。     

聚丙烯/蒙脱土纳米复合材料的制备与性能

合成了TiCl4/MgCl2/MMT插层催化剂,通过原位聚合制备了聚丙烯/蒙脱土纳米复合材料。X射线衍射结果表明:蒙脱土在聚丙烯基质中达到了纳米级分散。与纯聚丙烯(PP5004)相比,聚丙烯/蒙脱土纳米复合材料的力学性能、维卡软化点、热变形温度以及热分解温度都有所提高。     

Rheology,Crystallization Kinetics and Mechanical Properties of HDPE/Vinyl-POSS Nanocomposites

Polyhedral oligomeric silsesquioxane (POSS) is usually prepared from the hydrolytic condensation of organotrialkoxysilanes. The rheology, non-isothermal crystallization kinetics and mechanical properties of high density polyethylene (HDPE)/vinyl-containing POSS (V-POSS) nanocomposites were investigated. The results show that the molten HDPE/V-POSS belong to pseudoplastic fluid. The V-POSS can accelerate the nucleation of HDPE at starting stage of crystallization. However, it will decrease the crystallization ability of HDPE in the subsequent crystallization process. The modified Avrami analysis by Jeziorny can well explain the crystallization behaviour of HDPE/V-POSS. The yield strength and tensile modulus of nanocomposites both increase when V-POSS content is 6%.     

熔融共混制备聚乳酸/蒙脱土纳米复合材料及其性能研究

通过熔融共混制备了聚乳酸/蒙脱土纳米复合材料,研究了蒙脱土对聚乳酸结晶性能、热稳定性、力学性能以及动态力学性能的影响。研究结果表明:蒙脱土对聚乳酸的熔体结晶过程起促进作用;聚乳酸/蒙脱土纳米复合材料的起始热分解温度随蒙脱土含量的增加而升高;适量的蒙脱土可对聚乳酸起增强作用,蒙脱土含量小于5%时,还可改善聚乳酸的韧性。动态力学性能分析结果表明:蒙脱土对聚乳酸的玻璃化转变温度无明显影响但,损耗因子随蒙脱土含量的增加而减小。     

HDPE蠕变行为的研究

研究HDPE的蠕变行为不仅有助于从分子运动机理上揭示聚合物的黏弹性行为,还能够预测材料使用过程中的尺寸稳定性及长期承载能力,减小工程设计误差,确保材料使用的安全性,因而具有重要的理论意义和实用价值。回顾了蠕变理论的发展,综合了近年来有关HDPE蠕变行为及形变机理的研究进展,并以HDPE单向拉伸格栅为例简要分析了此项研究的发展及应用前景。     

PE-LD／凹凸棒土纳米粒子复合材料的制备与性能研究

采用超声波分散方法将凹凸棒土(AT)在甲苯中进行分散，然后采用硅烷偶联剂KH570对凹凸棒土纳米棒晶进行表面处理，将经上述处理的凹凸棒土与低密度聚乙烯(PE-LD)复合制备纳米粒子复合材料，研究了纳米粒子复合材料的晶体结构与性能。结果表明，凹凸棒土在一定程度上可以提高PE-LD的综合性能。     

云母粉改性高密度聚乙烯的汽油阻隔性

以片状云母粉为阻隔改性剂,与高密度聚乙烯(PE–HD)熔融共混,以改善其对汽油的阻隔性,考察云母粉形貌、含量等因素对PE–HD/云母粉复合材料阻隔性、熔体流动性以及力学性能的影响。结果表明,云母粉可显著提高复合材料对汽油的阻隔性,但熔体流动速率(MFR)与断裂伸长率降幅明显,高径厚比的云母粉对复合材料的汽油阻隔性提升更为显著,但径厚比过大不利于阻隔性的进一步提升,并会导致材料MFR和断裂伸长率进一步下降;当云母粉含量开始增加时,复合材料的汽油阻隔性明显提升,拉伸强度与缺口冲击强度上升,而MFR和断裂伸长率下降,当裂纹发展方向垂直于云母片面积方向时,缺口冲击强度提高更为显著;随着云母粉含量继续增加,复合材料的汽油阻隔性趋于稳定,拉伸强度与缺口冲击强度却明显下降。当径厚比为180的云母粉质量分数为30%时,复合材料具有最佳的综合性能,其汽油浸泡后的拉伸强度保持率显著高于纯PE–HD。     

高密度聚乙烯／膨胀石墨导电复合材料的研究

用溶液插层制备的马来酸酐接枝聚乙烯／膨胀石墨(EG)(60／40)作为EG母料，以不同用量、方法或条件与PE-HD熔融共混后模压为板材，研究了复合材料的加工-结构-性能关系。结果表明：熔体捏合或挤出时物料受剪切程度越小，材料中EG粒子的尺寸、形状比越大，粒子内部EG-聚合物复合结构的规整性也越好，材料的导电逾渗阈值就越低，定EG含量下的电导率σ就越高而拉伸强度(σt)越低。     

宽峰高相对分子质量高密度聚乙烯专用料的研制

通过淤浆法小试聚合装置合成了不同相对分子质量的高密度聚乙烯粉末,对聚合工艺条件对产物物性的影响进行了研究。同时,考察了不同相对分子质量的聚乙烯共混合成宽峰聚乙烯专用料的规律。结果表明:通过调整聚合工艺条件,在淤浆法小试聚合装置聚合产物的相对分子质量可调;不同相对分子质量的聚乙烯粉末共混可以制备宽峰HDPE;合成的宽峰HDPE专用料的综合力学性能优良,在树脂研究院进行加工,性能良好。