测接触角法确定偶联剂的最佳用量

偶联剂是一类能在无机填料和聚合物基材之间形成“分子桥”、改善两者之间相容性或提高两者之间相互作用能力的化合物。将经偶联剂改性的无机填料填充到聚合物中可以制得成本低、性能好的复合材料。由于偶联剂用量多少将对复合材料的性能产生较大影响,因此建立一种准确、简便地确定偶联剂最佳用量的方法有着十分重要的理论和实际应用意义。     

硅灰石矿物发光原料中Fe2+的去除与CaSiO3∶Eu3+的光谱特性

提出了用草酸．邻菲哕啉去除硅灰石中Fe^2 的方法，研究了浸取剂的浓度、浸取时间和温度等条件对Fe^2 的去除率的影响，在最佳的浸取条件下，Fe^2 的去除率达到98．35％。在去除猝灭剂后的硅灰石矿物中，掺加适量的稀土激活剂Eu^3 ，通过高温固相法制成荧光发光材料，发光强度明显提高，接近于化学试剂合成的发光材料。     

硅灰石填充聚丙烯复合材料性能的研究

本文研究了硅灰石填充聚丙烯(含乙烯22％)复合材料的热学、广角X-射线衍射和动态力学性质。复合材料中β晶含量随硅灰石含量增高而增加。试样的熔融及结晶行为表明,所有硅灰石填充试样均含有α和β两种晶型,4个结晶熔融转变;而未填充试样只有a晶型,2个结晶熔化转变。在DSC曲线上,β晶在升温过程中转变成α晶型。硅灰石填料对聚丙烯动态力学性能的影响表明,硅灰石起到了增强剂和β晶成核剂的双重作用,填料硅灰石已进入聚丙烯的结晶相。     

纳米孔硅灰石载药抗菌止血材料的研究

采用溶胶-凝胶法,以聚氧乙烯-聚氧丙烯-聚氧乙烯三嵌段共聚物(P₁₂₃)为模板剂,合成了纳米孔硅灰石(np-WT),用np-WT载盐酸万古霉素研制了一种新型的载药抗菌止血材料,并对其止血性能进行了研究。结果表明：np-WT具有排列有序的纳米孔道结构,其孔径在2 nm左右,高比表面积的np-WT能够明显地缩短体外部分凝血活酶时间(APTT)和凝血酶原时间(PT)。载药np-WT能够在磷酸缓冲溶液(PBS)中缓慢地释放药物,载药np-WT对其凝血性能没有明显的影响。载药np-WT对大肠杆菌有很好的抗菌作用,细胞毒性实验表明：载药np-WT无细胞毒性。载药np-WT具有很好的止血性能,能够阻止兔背部伤口的流血和缩短其流血时间。     

硅灰石填充尼龙66的力学性能

硅灰石填充尼龙６６的力学性能王雪芹，李滨耀（中国科学院长春应用化学研究所长春１３００２２）关键词硅灰石，尼龙６６，填充改性，力学性能硅灰石是一种工业矿物，具有完整的短纤维针状结构，在塑料的填充改性中，能够与石棉、滑石、云母等相媲美，在欧美占无机填料市...     

电泳法研究改性硅灰石的表面性质

本工作用测定水合金属氧化物等电点的方法,作为评定在硅灰石表面镁的包膜技术,为硅灰石的一物多用提供了新的途径;亦为在硅灰石表面包覆其他金属氧化物找到了一种新的方法。 本工作还研究了影响镁包覆的几种因素,结果表明,在硅灰石表面镁包膜的最佳条件为:pH=10,氢氧化镁溶胶的浓度为0.1mol·1~(-1),平衡时间为1小时,液固质量比为10以上。     

短纤维/硅树脂复合材料的性能研究

分别用ＰＥＴ短纤维和硅灰石（无机针状晶须）增强甲基乙烯基硅树脂,研究了纤维长度、含量与复合材料力学性能的关系,并考察了增强纤维对硅树脂热稳定性的影响。结果表明：ＰＥＴ短纤维增强硅树脂复合材料的拉伸强度、模量和硬度显著提高,断裂伸长率下降;ＰＥＴ纤维长径比在１８０～３００范围内时,复合材料的拉伸强度增大;硅灰石增强的复合材料强度、模量及硬度提高相对较小,断裂伸长率随强体用量增多,先增加而后降低,存在     

Comparative study of the mechanical and wear performance of short carbon fibers and mineral particles (Wollastonite,CaSiO3) filled epoxy composites

To improve the mechanical and tribological performance, two kinds of wollastonite fillers (fine or coarse) and short carbon fibers (5–15 vol %) were, respectively, incorporated into an epoxy resin. Fine wollastonite fillers remarkably enhanced the flexural modulus, strength, and toughness of the resin at some filler contents (i.e., 10 vol %) simultaneously, while coarse wollastonite fillers and short carbon fibers impaired most of mechanical properties except the modulus. The small particle size, low aspect ratio as well as the good adhesion to the epoxy matrix of the fine wollastonite particles are believed to be responsible for the improved strength and toughness. Tribological tests were performed under sliding and low amplitude oscillating wear conditions. All fillers enhanced the wear resistance and reduced the sliding coefficient of friction but to a different extent. Under sliding wear conditions, fine wollastonite particle‐filled epoxy displayed the highest wear resistance because of the formation of an effective transfer film and the low abrasiveness of the fillers. Under low amplitude oscillating wear conditions, both wollastonite fillers showed much higher wear resistance than short carbon fibers regardless of the filler content. The better adhesion between the wollastonite fillers and the epoxy matrix is responsible for the higher wear resistance under oscillating conditions. The wear tracks were inspected by microscopy to analyze the corresponding wear mechanisms. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 854–863, 2006     

Devitrification behaviour of CaO−MgO(Y2O3)−SiO2 glasses

In this paper a thermoanalytical study of the kinetic parameters and mechanism of the devitrification process of CaO·SiO₂, 1.6CaO·0.4MgO·2SiO₂ and 1.4CaO·(0.6/3)Y₂O₃·2SiO₂ is reported. The experimental results suggest that, in the studied glasses, a surface nucleation process is operative; however, in finely powdered samples, that soften and efficiently sinter before devitrifying, surface nuclei behave as bulk nuclei. In this case lamellar crystalline structures are obtained.     

Optimization of scratch resistance and mechanical properties in wollastonite‐reinforced polypropylene copolymers

The aim of this research was to establish a balance between scratch resistance and scratch damage visibility in the wollastonite‐filled heterophasic polypropylene copolymers.The influences of various factors including the surface hardness, elasticity, friction coefficient, and combinations thereof on the scratch behavior (scratch resistance and scratch visibility) were elucidated. Using micro‐scale and nano‐scale scratch tests and image analysis techniques, the scratch hardness, scratch depth, and scratch visibility of the composites were characterized.It was found that the introduction of wollastonite in the polypropylene copolymer matrix contributes to ductile fracture behavior because of an induced crystallization alteration. Accordingly, the scratch resistance of reinforced composites revealed an increase as a result of higher stiffness of the wollastonite as well as contribution of new crystalline structure. The addition of siloxane to the composites improved the resistance to surface damage by lowering the surface friction coefficient originated from enhanced chain mobility. Simultaneous addition of high density polyethylene and siloxane induced a significant influence on the resistance to the scratch damage. Copyright © 2015 John Wiley & Sons, Ltd.