【作者】 高进；

【导师】 王依民；

【作者基本信息】 东华大学 ， 高分子化学与物理， 2009， 硕士

【摘要】 混凝土是世界上用量最大、使用最广泛的建筑材料之一,作为一种重要的结构材料,其强度和耐久性一直得到人们的关注。纤维增强是水泥基材料高性能化的主要途径,纤维的分布状况以及纤维的掺量对混凝土的性能有很大影响。因此人们迫切需要一种纤维能够掺杂在增强纤维中间,通过特定的检测手段表征出纤维的分布状况,从而采取措施改善分散效果,提高纤维混凝土的性能。聚乙烯醇是一种性能优良的、用途广泛的多羟基聚合物。由于聚乙烯醇具有良好的相容性、成膜性、成纤性和粘接性等优点,且具有较好的力学性能,在纤维、薄膜、粘合剂和生物医学材料等领域具有广泛的用途,特别是这些年广泛用作混凝土增强材料。超细硫酸钡是指一次粒子的平均粒径在10～100μm范围内,且100μm以下的粒子占90%以上的硫酸钡粒子,是一种广泛应用的白色无机盐中性填料。具有优越的光学性能,良好的分散性和较好的吸收性能,而且耐光性和耐腐蚀性较强,被广泛应用于涂料、橡胶、医学造影等方面。从理论上说,超细硫酸钡也是高分子复合材料理想的功能和增强材料。本论文研究了超细硫酸钡/聚乙烯醇复合体系及复合纤维的结构与性能以及在混凝土增强材料中的初步应用研究。为了提高复合纤维的造影和检测性能,复合纤维中硫酸钡含量最高达70wt%,并对复合体系的流变和结晶性能以及复合纤维的结构和性能进行了研究。结果表明:1.BaSO₄/PVA复合体系的动态流变测试结果表明:60℃时BaSO₄添加量为60wt%的冻胶体系具有最好的综合性能:其体系具有较高的储能、损耗模量,较低的耗散系数与流动活化能。2.对BaSO₄/PVA复合纤维的结晶行为的研究表明:BaSO₄无机粒子的加入使PVA的结晶结构变得复杂,改变了PVA的结晶维数。总体来说,BaSO₄无机粒子的存在降低了PVA的结晶度。且随BaSO₄含量的增加复合纤维的结晶度和结晶行为变差。3.对复合纤维的结构与性能的研究表明:在BaSO₄含量超过50wt%时,体系内部发生相转变,BaSO₄无机粒子由原来的分散相变成了连续相;BaSO₄无机粒子的加入使复合纤维的各项力学性能都有一定的影响,但仍能满足后加工要求;随BaSO₄含量的增加,复合纤维的造影效果变好,40wt%BaSO₄/PVA的复合纤维开始具有良好的造影效果,可作为功能材料应用于相关领域。更多还原

【Abstract】 Concrete is one of the most consumable and the most versatile building materials.As an important structure material,its strength and durability have been paid more and more attention.The fiber reinforcement is the principal way to get high performance concert,and the amount and distribution of fiber in matrix have a great influence on the performance of the composite material.So a detectable fiber is needed in a great urgent. Thereby countermeasure can be adopted to improve the fiber dispersion and the performance of the concrete.Poly（vinyl alcohol） is a polyhydroxylated polymer with excellent performance and extensive usage.Because of its good compatibility, film-forming property,fiberizability,cohesiveness and outstanding mechanical properties,PVA is applied widely in the fields of fiber, membrane,adhesive and biomaterials.Especially,it popular used as concrete reinforced material in the recent years.Meanwhile superfine barium sulfate powder is a white mineral with mean particle diameter between 10～100μm.It is always used as filler applied in paint,rubber and medical imaging owning to its excellent optical property,dispersivity, adsorption ability and photostability.Superfine barium sulfate is ideal materials for functionalization and reinforcement of polymer matrix theoretically. In this paper,structure and properties of BaSO₄/PVA composite fiber were studied.In order to improve the imaging property,a series amount of BaSO₄ was employed.The rheological property of the blend and the crystallization behavior,structure and properties of the composite fibers were also investigated.The conclusions are as the follows:1.The dynamic rheological behavior measurement of BaSO₄/PVA blend system showed that the blend system with 60wt%BaSO₄ presents the best comprehensive properties:when the temperature is 60℃,the system has high storage modulus,high loss modulus,low loss tangent and activation energy.2.The non-isothermal crystallization kinetics and crystallization characterization of the composite fiber showed that the addition of BaSO₄ particles made the crystal structure complicated,the crystal dimension changed.The crystallinity of the composite fiber was decreased with the increase of BaSO₄ content.3.Structure and morphology of BaSO₄/PVA fibers demonstrated that phase transition happened inner the blend system when the BaSO₄ content up to 50wt%;The mechanical properties of the fibers was influenced by the addition of BaSO₄ particles,However,it also can meet the requirements as concrete reinforcement.The imaging property of the composite fiber is improved when BaSO₄ content increasing.The fiber has outstanding imaging property when BaSO₄ content up to 40wt%.And it can be used as a functional material applied in related field.更多还原