Magnesium hydroxide modified by 1‐n‐tetradecyl‐3‐carboxymethyl imidazolium chloride and its effects on the properties of LLDPE

In this study, Mg(OH)₂ (MH) was first modified by 1‐n‐tetradecyl‐3‐carboxymethyl imidazolium chloride ([C₁₄cim]Cl), an imidazolium ionic liquid, and then the modified MH ([C₁₄cim]Cl‐MH) was incorporated into linear low‐density polyethylene (LLDPE) by melt‐mixing to obtain the LLDPE/[C₁₄cim]Cl‐MH composites. The interaction between [C₁₄cim]Cl and MH was investigated by Fourier transform infrared spectroscopy (FT‐IR). The thermal decompostion behaviors of the LLDPE/[C₁₄cim]Cl‐MH composites were characterized by thermogravimetric analysis (TGA). The flame retardance, tensile and Izod Impact properties of the LLDPE/[C₁₄cim]Cl‐MH composites were tested. For comparison, the LLDPE/MH composites and LLDPE/SA‐MH composites (SA‐MH is stearic acid) were prepared and their properties were studied in the same way. It was found that [C₁₄cim]Cl interacted with MH via chemical bonding, and served as an efficient lubricant and compatibilizer for MH and LLDPE, leading to great improvements of processability and mechanical properties of the LLDPE/[C₁₄cim]Cl‐MH composites. The LLDPE/[C₁₄cim]Cl‐MH composites also showed a remarkably promoted char formation and effectively eliminated melt drips, thus endowing the composites with sufficiently high flame retardancy. POLYM. ENG. SCI., © 2011 Society of Plastics Engineers     

Toughening of polylactide with natural rubber grafted with poly(butyl acrylate)

Natural rubber grafted with poly(butyl acrylate) (NR‐g‐PBA) in an attempt to toughen polylactide (PLA) was prepared by grafting butyl acrylate onto natural rubber (NR) through emulsion polymerization. The purified NR‐g‐PBA was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. NR‐g‐PBA/PLA blend and NR/PLA blend were prepared with a Haake internal melt mixer. The morphology and mechanical properties of the blends were investigated as a function of rubber content. Observations by scanning electron microscopy showed that the spherical‐particle‐dispersed phase appearing in the NR/PLA blend was not found in the NR‐g‐PBA/PLA blend, which showed that NR grafted with PBA is compatible with PLA, and accounted for the efficient toughening effect on PLA. The elongation at break and the impact strength were significantly improved with an increase in NR‐g‐PBA content. The thermal stability of PLA decreased when blended with NR but was retained with NR‐g‐PBA. Copyright © 2011 Society of Chemical Industry     

Broadband luminescence and emission enhancement

Three novel quinoline– and fluorene–coumarin hybrids were prepared and characterised by Fourier Transform–infrared spectroscopy, proton and carbon nuclear magnetic resonance spectroscopy, mass spectrometry, elemental analysis and ultraviolet–visible spectrophotometry. Their photoluminescence properties were investigated. All of these hybrid molecules exhibited a broadband emission from ca. 450 to 800 nm when excited by a 325 nm helium–cadmium laser at room temperature. Importantly, the fluorene–coumarin hybrid shows a very bright red emission at ca. 650 nm and displays up to a 10‐fold increase in fluorescence emission intensity, as compared with the other samples. The experimental results confirm that remarkable enhancements in the fluorescence emission intensity can be obtained by introducing a fluorene group into the azo‐bridged coumarin‐based π‐conjugated framework. The geometry structures and frontier orbitals are calculated by the ab initio Hartree–Fock method.     

微波活化粉煤灰及其应用研究进展

阐述了微波活化粉煤灰的激发机理及其研究进展,并讨论了微波在粉煤灰改性中存在的问题及今后的发展趋势.     

食品专业英语词汇教学探讨

鉴于食品专业英文文献词汇量大,学生感觉记忆词汇难,而食品专业英语教学时数却普遍较少的实际情况。笔者提出了食品专业英语词汇教学的基本策略及其实施要点。通过向学生传授食品专业英语词汇的构造规律,以增加学生的学习兴趣和信心,减轻学生的学习负担,达到较好的教学效果。     

钼尾矿-粉煤灰-炉渣承重蒸压砖的研制

本文利用栾川南泥湖钼尾矿、粉煤灰、炉渣为原料,以石灰、脱硫石膏为激发剂,通过正交设计研究生产承重蒸压砖的试验方法和工业试验.探寻出了影响钼尾矿-粉煤灰-炉渣承重蒸压砖强度的主要因素是成型压力,其次是水固比、骨料掺量、困料时间、钼尾矿与粉煤灰的质量比.XRD显示,钼尾矿-粉煤灰-炉渣经过蒸压产生了托勃莫莱石和方解石等水化产物,这些水化产物将未反应粗料粘结在一起,组成以粗颗粒为骨架的混凝土式结构,使得制品具有一定强度.对制品进行了性能测试表明:除具有较好的强度外,其冻融性、石灰爆裂、吸水率、耐碱、耐盐性能均良好,强度完全可以达到国家标准JC 239-2001《粉煤灰砖》规定的MU20级要求.经洛阳市金鉴工程质量检测中心检测,其各项性能均符合国家标准技术规定,放射性检验为A类建筑材料.     

浅谈大卷装拉丝丝饼常见成形缺陷的改善

通过对大卷装拉丝机丝饼成形缺陷的改善试验研究,找出影响丝饼成形的因素,找到解决方案并实施,最终确定了适合的拉丝工艺参数。经过试验验证,效果良好,提高了大卷装丝饼纱的产品质量,同时提高了生产效率。     

微孔发泡聚苯乙烯力学性能的分析与探讨

制备了发泡量相同的微发泡聚苯乙烯,采用扫描电镜(SEM)和Image-pro图像处理软件对微发泡聚苯乙烯的微孔尺寸进行了观察和统计;建立微球模型,分析了微孔尺寸大小对微发泡聚苯乙烯力学性能的影响.结果表明:细小而均匀的泡孔对微发泡聚苯乙烯力学性能的提高有较明显的促进作用,微球模型的计算结果与宏观力学性能的影响规律有很好的重现性.     

亚麻织物阻燃整理的研究现状与发展趋势

介绍了阻燃剂阻燃的基本原理,及其按照不同标准的分类,同时介绍了各类阻燃剂的代表物质及它们的应用领域;重点阐述了关于亚麻纤维织物常见的阻燃整理方法的研究现状,以及今后新型阻燃剂体系应朝着无卤、低烟、无毒方向发展的趋势;确定了应用于亚麻纤维织物的阻燃整理剂在实现绿色环保的同时,提高亚麻纤维织物阻燃综合性能的发展目标.     

PA66/PTFE复合材料的摩擦磨损性能

采用机械共混的方法制备了PA66/PTFE复合材料,研究了聚四氟乙烯(PTFE)改性尼龙66( PA66)复合材料的摩擦磨损性能,并采用扫描电镜( SEM)观察了材料的磨损表面.结果表明:PTFE的加入可以有效改善尼龙66的摩擦性能,当PTFE质量分数为9％时,摩擦系数为纯PA66的57％左右,磨损量为纯PA66的43％左右,综合耐磨性最好.磨损面的扫描电镜观察发现,材料的磨损以黏着磨损和磨粒磨损为主,PTFE在共混体系中形成了微纤结构.