In this study, two kinds of mineral fillers, bentonite (BNT) and barite (BRT), were incorporated into low density polyethylene (LDPE) by extrusion process. Silane treatment was applied to BRT and BNT surfaces in order to increase their compatibility with LDPE matrix. Surface characteristics of fillers were examined by Fourier transformed infrared spectroscopy (FTIR). LDPE-based composites were prepared at a constant concentration of 10%wt for each additives. Test samples were shaped by injection molding process. Mechanical, thermo-mechanical, water repellency, melt-flow and morphological characterizations of LDPE and its composites were performed by tensile and impact tests, dynamic mechanical analysis (DMA), water absorption test, melt flow index (MFI) measurements and scanning electron microscopy (SEM) technique, respectively. Test results showed that surface treatments led to increase for final properties of composites since they promoted to stronger adhesion between minerals and LDPE matrix compared to untreated ones. Tensile and impact strength values, storage modulus and glass transition temperature of LDPE were improved by inclusion of silane treated minerals. BRT and BNT additions caused no remarkable changes with regard to MFI of LDPE. Additionally, silane modified mineral filled composites exhibited remarkable water resistance behavior. According to SEM analysis of composites, silane treated BNT and BRT containing samples displayed homogeneous dispersions into LDPE phase whereas debondings were observed for untreated BNT and BRT filled composites due to their weak adhesion to polymer matrix.

中文翻译：

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膨润土和重晶石负载低密度聚乙烯复合材料的物理和机械性能：矿物表面硅烷化的影响

在这项研究中，两种矿物填料，膨润土 (BNT) 和重晶石 (BRT)，通过挤出工艺掺入低密度聚乙烯 (LDPE) 中。硅烷处理应用于 BRT 和 BNT 表面，以增加它们与 LDPE 基体的兼容性。通过傅里叶变换红外光谱（FTIR）检测填料的表面特性。对于每种添加剂，以 10%wt 的恒定浓度制备基于 LDPE 的复合材料。测试样品通过注塑成型工艺成型。通过拉伸和冲击试验、动态力学分析 (DMA)、吸水率试验、熔体流动指数 (MFI) 测量和扫描电子显微镜对 LDPE 及其复合材料的机械、热机械、拒水性、熔体流动和形态特征进行了表征(SEM) 技术。测试结果表明，表面处理导致复合材料的最终性能提高，因为与未处理的相比，它们促进了矿物和 LDPE 基体之间更强的粘附。通过包含硅烷处理的矿物，LDPE 的拉伸和冲击强度值、储能模量和玻璃化转变温度得到改善。BRT 和 BNT 添加对 LDPE 的 MFI 没有造成显着变化。此外，硅烷改性矿物填充复合材料表现出显着的防水性能。根据复合材料的 SEM 分析，含硅烷处理的 BNT 和 BRT 样品显示出均匀分散到 LDPE 相中，而未处理的 BNT 和 BRT 填充复合材料由于对聚合物基体的弱粘附而观察到剥离。