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首页> 外文期刊>Journal of Applied Polymer Science >Thermal and mechanical properties of aramid-based titania hybrid composites
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Thermal and mechanical properties of aramid-based titania hybrid composites

机译：芳纶基二氧化钛杂化复合材料的热力学性能

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The sol-gel process has been used to prepare various types of aramid-titania hybrid materials. Specifically, a, mixture of m- and p-phenylenediamines was reacted with. terephthaloyl chloride to produce linear polyamide chains in a dimethylacetamide solvent. Various proportions of tetrapropylorthotitanate (TPOT) were added, and its subsequent hydrolysis-condensation in the polymer solution produced a titania (TiO2) network in the aramid matrix. Thin films prepared from these materials were tested for their tensile strength, which was found to decrease with increasing proportions of titania. To remedy this through chemical bonding between the matrix and the inorganic network: a slight excess of terephthaloyl chloride or 1,3,5-benzenetricarbonyl chloride was added near the end of the polymerization reaction. These aramid chains were thus end-capped with single or double carbonyl chloride groups. This allowed the chains to be further modified, with aminophenyltrimethoxysilane end caps. Chemically bonding the titania network to the aramid chains was then achieved by in situ hydrolysis-condensation of TPOT along with that of aminophenyltrimethoxysilane. In this way, thin transparent and tough films could be obtained with up to 30 wt % titania. The values of the tensile strength in the case of bonded hybrid materials increased with the addition of titania, and the polyamide system with nonlinear end groupings showed larger increases than did those with the linear chains ends. The systems with linear and nonlinear aramid chain ends were able to withstand maximum tensile stresses of the order of 193 and 246 MPa, respectively. This is presumably due to the extensive bonding between the polymeric chain ends and the inorganic phases as compared to the unbonded system. The thermal decomposition temperature of these composites was found to be in the range of 500-600 degrees C: and the overall weight loss was found to be minimized in an inert atmosphere. (C) 1998 John Wiley & Sons, Inc. [References: 20]
机译：溶胶-凝胶法已经用于制备各种类型的芳族聚酰胺-二氧化钛杂化材料。具体地，使间苯二胺和对苯二胺的混合物反应。对苯二甲酰氯在二甲基乙酰胺溶剂中生产线性聚酰胺链。添加各种比例的四丙基甲钛酸酯（TPOT），其随后在聚合物溶液中的水解-缩合在芳族聚酰胺基体中产生二氧化钛（TiO2）网络。测试了由这些材料制成的薄膜的拉伸强度，发现该拉伸强度随二氧化钛比例的增加而降低。为了通过基体和无机网络之间的化学键来解决此问题：在聚合反应快要结束时，添加了稍微过量的对苯二甲酰氯或1,3,5-苯三羰基氯。这些芳族聚酰胺链因此被单个或两个羰基氯基团封端。这允许使用氨基苯基三甲氧基硅烷端基进一步修饰链。然后通过TPOT和氨基苯基三甲氧基硅烷的原位水解缩合，将二氧化钛网络化学键合到芳族聚酰胺链上。以此方式，可以获得具有高达30重量％的二氧化钛的薄的透明且坚韧的膜。结合杂化材料的情况下，抗拉强度的值随二氧化钛的增加而增加，具有非线性端基的聚酰胺体系比具有线性链端的聚酰胺体系表现出更大的增长。具有线性和非线性芳族聚酰胺链端的系统能够分别承受193 MPa和246 MPa的最大拉伸应力。据推测，这是由于与未键合体系相比，聚合物链端与无机相之间的键合广泛。发现这些复合物的热分解温度在500-600℃的范围内：并且发现在惰性气氛中总的重量损失最小。 （C）1998 John Wiley＆Sons，Inc. [参考：20]

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