蒙脱土对脲醛树脂性能的影响

以有机蒙脱土(OMMT)作为脲醛树脂(UF)胶粘剂的改性剂,制备UF/OMMT纳米复合材料;然后将其用于刨花板的制备,并采用红外光谱(FT-IR)法和X-射线衍射(XRD)法对纳米复合材料的结构进行了表征。结果表明:刨花板的力学性能随OMMT含量增加呈先升后降(或先升后降再升)态势,并且在w(OMMT)=3%时相对较好;当w(OMMT)=1%时,经硅烷偶联剂(KH-550)处理后的OMMT在UF反应终了阶段加入时,刨花板的综合力学性能相对最好;在纳米复合材料体系中,OMMT的层状纳米片层已被剥离,并且OMMT和UF之间发生了一定程度的化学反应,而偶联剂和OMMT之间并没有形成化学键。     

有机蒙脱土对三元共混胎面胶（NR／BR／SBR）结构与性能的影响

采用机械共混法制备了天然橡胶（NR）／顺丁橡胶（BR）／丁苯橡胶（sBR）／有机蒙脱土（OMMT）复合材料;用X射线衍射（xRD）和扫描电镜（SEM）对复合材料的结构进行了表征,并研究了OMMT对复合材料的物理机械性能、硫化性能、热稳定性能的影响。结果表明,该复合材料为插层型复合材料,添加5phrOMMT有利于提高复合材料力学性能、耐磨性能、热稳定性能,促进硫化,降低最低扭矩。     

固硫灰渣对减水剂吸附作用研究

采用离心法对含减水剂的燃煤灰渣-水泥胶凝系统进行分离,用紫外-可见分光光度计研究固硫灰渣对聚羧酸和脂肪族减水剂的吸附规律。结果显示,固硫灰渣-水泥系统对减水剂的吸附量大于粉煤灰-水泥系统;燃煤灰渣掺量越大,对减水剂的吸附量也越大;相比脂肪族减水剂,聚羧酸减水剂吸附量对燃煤灰渣掺量比较敏感。研究表明,当固硫灰渣用作水泥混凝土掺合料时,从减水剂吸附的角度来看,掺量较低时适合采用聚羧酸减水剂,而掺量较高时宜采用脂肪族减水剂。     

高塔保水缓释肥生产技术与产业化开发

将保水剂和肥料在材料和功能上进行复合一体化,开发研制了具有抗旱保水和缓释长效功能的肥料。该保水缓释肥不仅解决了目前农业生产上使用的肥料不具有吸水、保水的缺陷,而且还可解决高水溶性肥料养分速效、释放快、有效期短、养分释放与作物吸收不协调、易淋失固定或挥发等造成浪费资源和污染环境的问题。     

PCPZ/Mg（OH）2对高密度聚乙烯热性能的影响

通过苯氧基环三磷腈(PCPZ)、氢氧化镁[Mg(OH)2]添加量以及二者协同对高密度聚乙烯(PE–HD)热性能影响的实验研究,探讨了PCPZ和Mg(OH)2对PE–HD热性能的影响规律,并对其影响原因进行了分析。结果表明,在PE–HD/PCPZ混合体系中,随着PCPZ含量的增加,材料的热稳定性和残炭率也随之增大,当PCPZ质量分数为44%时,800℃时的残炭率为33.3%。PCPZ/Mg(OH)2同时作用于PE–HD时对材料的热稳定性有协同效应,当PCPZ,Mg(OH)2质量分数分别为15%,35%时,协同效果最佳,800℃时的残炭率约为35.2%。     

中欧钢筋混凝土筒仓设计规范比较

通过实际工程案例,对比分析采用欧洲规范《Eurocode 1-Actions on structures-Part 4：Silos and tanks》（EN 1991-4：2006）和中国规范《钢筋混凝土筒仓设计规范》（GB 50077-2003）计算钢筋混凝土筒仓结构时,贮料水平压力、竖向压力、仓壁上单位周长上总摩擦力的差别,以期指导工程设计。     

工科专业实践环节与课外科技活动结合模式的探索

在国内外竞争日趋激烈的今天,高校加强大学生创新实践能力的培养,对提高大学生素质极其重要。本文根据高校专业实践环节的特点,分析了学生实践能力培养的现状及形成原因,积极探索大学生课外科技活动与专业实践环节结合的途径和方法。     

三层PE热收缩带补口材料抗压性能测试研究

选取目前国内外几种典型的三层聚乙烯(PE)热收缩带补口材料产品,通过改进的压痕试验(加载压力选用5和10 MPa,试验温度选用23℃和50℃,延长加载时间至360 h)测定其压深比(压痕深度/原始厚度),讨论了结合热熔胶、试验温度、加载压力等因素对热收缩带压深比的影响,得到了能够表征目前常见PE热收缩带抗压性能的一般性规律,即高温测试条件下是否结合热熔胶对PE热收缩带的压深比影响不大,室温测试条件下结合热熔胶的PE热收缩带的压深比较高;试验温度对PE热收缩带压深比的影响最大,其次为加载压力,PE热收缩带压深比随试验温度和加载压力的升高而增加。经单个热收缩带产品的抗压性能测试验证,除加载压力对压深比的影响略大于试验温度的影响外,其余均符合所得到的一般性规律。     

Chemical and Physical Characterization of Donkey Abdominal Fat in Comparison with Cow, Pig and Sheep Fats

The objective of this research was to investigate the physicochemical properties of donkey fat. Results show that donkey fat contains 59.38 % unsaturated fatty acids, 38.37 % saturated fatty acids, and 0.21 % trans fatty acids. The sn-2 monoglyceride present in donkey fat contain 67.91 % unsaturated fatty acids and 30.97 % saturated fatty acids. Donkey fat is also characterized by a total tocopherol content of 8.59 mg/100 g fat (7.90 mg/100 g fat α-tocopherol, 0.51 mg/100 g fat β + γ-tocopherol, and 0.18 mg/100 g fat δ-tocopherol), 0.0032 mg/100 g fat cholesterol, an acid value of 0.091 KOH (mg/g), an iodine value of 76.47 g/100 g, a peroxide value of 0.68 mmol/kg, a saponification value of 193 mg/g, a refractive index of 1.4666, and a specific gravity of 0.9144. The complete melting temperature was 40 °C. The content of unsaturated fatty acids (total and sn-2) in donkey fat is higher than cow, pig and sheep, while the content of trans fatty acids is lower. The tocopherol content is also higher in donkey fat compared to cow, pig and sheep fat. Interestingly, the fat with such processing has nearly no cholesterol. Generally speaking, donkey fat could be a good animal fat for human consumption.     

Effect of pulverized coal/carbon black hybrid fillers on mechanical properties and thermal stability of styrene butadiene rubber composites

Pulverized coal (coal) possesses a layered structure similar to graphite and is a potential reinforcing filler. In this paper, ball milling is used to reduce the particle diameter of coal. The coal is modified with KH-560 to obtain K-COAL and prepared K-COAL/styrene-butadiene rubber (SBR) composites. In addition, carbon black (CB) is modified to obtain CB-Si69, K-COAL and CB-Si69 are added to SBR in different ratios to prepare COAL/CB/SBR composites. The results show that the addition of K-COAL can improve the vulcanization performance, thermal stability, and mechanical properties of SBR composites, but the reinforcing effect is weak. In the COAL/CB/SBR composites, the vulcanization and mechanical properties of the composites gradually increase with the increase of CB, while those of the thermal stability decrease. The tensile strength of the 10 phr COAL/30 phr CB/SBR composite is 24.1 MPa, which is elevated by 1105% and 205% compared with the pure SBR and 40 phr K-COAL/SBR composites, respectively. The composites maintain high elasticity while the tensile strengths are greatly improved, and the mechanical properties are significantly enhanced. In conclusion, this paper provides a reference for the clean utilization of coal and shows new possibilities for finding new fillers to replace CB.