CMC和PAM对砂浆性能的影响

加气混凝土是一种新型建筑材料，自身具有许多优点。然而由于普通砂浆的保水性能不能适应加气混凝土的吸水性能，加气混凝土抹灰层经常出现开裂现象，这阻碍了加气混凝土的广泛应用。通过两类增稠剂CMC和PAM）对砂浆性能影响的试验研究发现，CMC可以大幅度提高砂浆的保水性能，从而可以较好地解决普通砂浆的保水性能与加气混凝土吸水性能不相适应的问题：PAM对普通砂浆的保水性能改善较少。     

纤维增强煤矸石轻骨料混凝土路用性能研究

以煤矸石为粗骨料,掺入不同掺量的聚丙烯纤维配制路面水泥混凝土,对混凝土的路用性能和微观结构进行了试验研究,分析了纤维的增强机理。结果表明,聚丙烯纤维可以减少混凝土中微裂缝的产生,抑制连通裂缝的发展,在一定掺量范围内能够有效提高煤矸石轻骨料混凝土的抗折强度和耐磨性,随着掺量的增加显著提高混凝土的抗渗性和抗冻性。煤矸石轻骨料混凝土中掺入聚丙烯纤维,可获得良好的路用性能。     

掺磷渣粉预拌砂浆的性能研究

本文针对磷渣粉对水泥浆体的凝结时间、砂浆稠度、保水率和强度的影响规律进行了试验研究。结果表明,掺入15%~25%的磷渣粉,对稠度、保水率影响较小,对砂浆28天强度影响不显著,同时可以明显延长水泥浆体的凝结时间。选用合适的原材料,并用20%的磷渣粉取代水泥,可以配制出强度等级从M10到M30全等级的预拌砂浆。     

Nonisothermal Crystallization Modeling and Simulation for Polypropylene/Nano CaSO4 Composites with Variations in Nanosizes and Wt.% of Loading

Avrami and Ozawa's combined analysis was employed to study the nonisothermal crystallization kinetics of Polypropylene (PP): CaSO₄ (of 12 and 22 nm) composites using a Differential Scanning Calorimeter (DSC). The parameters, such as Avrami's exponent (n) and growth rate constant (Z_t), that characterized the system of different nanosize composites and virgin PP, were determined. The relative degree of crystallinity as a function of temperature for PP/nano CaSO₄ composites at the same cooling rate and the Sigmoidal shape of curves indicate a strong interaction between PP molecules and the nanolayer, which leads to greater nucleation with a reduction in nanosizes. The theoretical combination of kinetic equations was found to be suitable to describe the physical phenomena of real system. The values of parameters n, Z_t and predicted time t for crystallization at a single cooling rate were obtained from the mathematical model.     

几种小分子酯类有机物对矿渣粉磨性能及矿渣水泥强度的影响

从筛余量、比表面积、粒径分布、胶砂强度、SEM分析等方面研究了几种小分子酯类有机物对矿渣粉磨和矿渣水泥强度的影响。结果表明：几种酯类物质均能降低矿渣筛余量,增加比表面积,提高3μm~32μm颗粒含量,对矿渣具有良好的助磨效果;酯类有机物分子的链长越长（对称结构除外）,官能团越多（官能团相距较远）,助磨效果越好;链长相同时,官能团数目的影响占主导地位。酯类物质的加入能使矿渣水泥水化产物Ca（OH）2成片层状紧密生长,能有效提高矿渣水泥的强度。     

塑料杯成型工艺及注塑模设计

本文对水杯的技术要求和工艺结构进行了分析,确定了工艺方案及模具形式。而且对水杯进行了相关数据的分忻与计算,根据分析结果选注塑机和注塑工艺,从而确定聚丙烯水杯设计思路及方案,最后在设计过程中运用Pro／E、Auto CAD软件进行注塑模结构设计与计算并绘制出模具总装图以及部分非标准图形。     

Kinetic analysis on spherulite growth rate of polypropylene catalloys

The kinetic analysis on melt-crystallization of polypropylene catalloys (PP-cats) was conducted through measuring their spherulite growth rates. A multiple melting behavior of PP-cats was found through differential scanning calorimetry (DSC) and the corresponding crystalline microstructures of PP-cats were studied by wide-angle X-ray diffraction (WAXD). The calculated T_m^o value of propylene homopolymer (PP) suggests an obvious melting point depression of PP-cats. Moreover, it is found that the existence of ethylene-propylene copolymer could result in the changes of crystalline microstructure of PP and the PP crystal is in favor of growing along (040) lattice plane of α-monoclinic crystal. The crystal growth rate of PP-cats decreases with the increase of ethylene-propylene copolymer content in PP-cats. A comparison of crystallization kinetics between PP-cats and virgin iPP through a modified Lauritzen-Hoffman model indicates that there appears a transition from regimes II to III in iPP and PP-cats containing low ethylene-propylene copolymer content. However, for the PP-cats containing high ethylene-propylene copolymer content, crystallization always processes in regime II. In addition, both calculated nucleation parameter (K_g) and the fold surface free energy (σ_e) for PP-cats increase with the increase of ethylene-propylene copolymer content, implying that the existence of ethylene-propylene copolymer is unfavorable for the surface nucleation of PP and regular folding of the molecule chain. It is believed that an increase in viscosity of the melts induced by different compositions could remarkably slow crystallization growth down, because under this condition surface nucleation dominates as compared with crystal growth.     

Irreversible dilation of NaCl contaminated lime-cement mortar due to crystallization cycles

The mechanism of damage occurring in NaCl contaminated materials has not been clarified yet. Apart from crystallization pressure, other hypotheses have been proposed to explain the cause of decay. Irreversible dilation has been observed in a few cases but has never been studied in a more systematic way. The aim of the research is to contribute to the modeling of this phenomenon.In the present paper the effect of NaCl on the hydric and hygric behavior of a lime-cement mortar is extensively studied. The results indicate that NaCl influences the hydric and hygric dilation behavior of the material. The material contaminated with NaCl shrinks during dissolution and dilates during crystallization of the salt. This dilation is irreversible and sufficient to damage the material after few dissolution/crystallization cycles. This behavior is not restricted to NaCl, but is observed in the presence of other salts as well (NaNO₃ and KCl). Outcomes of electron microscopy studies suggest that salts causing irreversible dilation tend to crystallize as layers on the pore wall.     

车用低TVOC聚丙烯材料的制备

采用一种高效的多孔材料作为总挥发性有机化合物(TVOC)吸附剂添加到车用聚丙烯材料中对其改性,通过顶空气相色谱-质谱联用(HS-GC-MS)检测了未改性车用聚丙烯材料的TVOC物质的种类,及通过顶空气相色谱-氢火焰离子化检测器联用(HS-GC-FID)检测了改性前后聚丙烯材料的TVOC释放量,结果表明:聚丙烯材料中的TVOC主要是烷烃类物质,多孔材料的加入有效地吸附了聚丙烯及加工过程中产生的长链烷烃,并在测试温度下不会解吸附,从而使得材料的TVOC含量达到客户的标准要求。     

长玻璃纤维增强聚丙烯复合材料的力学性能研究

采用熔体浸渍技术制备了长玻璃纤维母料(LGF/PP-g-MAH/PP)增强聚丙烯(PP)复合材料(LGF/PP)。通过双螺杆挤出机制备了同等配比的短玻纤增强聚丙烯(SGF/PP)复合材料。研究了LGF含量、环氧树脂(EP)和固化剂(2E4MZ)对LGF/PP复合材料的力学性能影响。结果表明:当LGF质量分数为35%～40%时,LGF/PP的综合力学性能最好,且明显优于同样组成的SGF/PP复合材料。EP和含固化剂(2E4MZ)的EP对LGF/PP复合材料的力学性能提高有一定的作用。SEM照片分析表明:EP的加入能改善玻纤与聚丙烯基体的界面粘接。