小中空容器专用双峰HDPE的结构与性能

采用傅里叶变换红外光谱仪、凝胶渗透色谱仪、差示扫描量热仪和毛细管流变仪分析了小中空容器专用双峰高密度聚乙烯(HDPE)的结构特点、力学性能和加工性能。结果表明:由于特殊的链结构和相对分子质量分布呈双峰的特点,小中空容器专用双峰HDPE的力学性能优异,具有高的耐环境应力开裂性;加工性能与小中空容器专用铬系单峰HDPE相当,加工范围略窄。     

双峰HDPE小中空容器专用树脂的结构与性能

采用凝胶渗透色谱仪、差示扫描量热仪、毛细管流变仪和电子万能试验机研究了双峰高密度聚乙烯(HDPE)小中空容器专用树脂的结构、力学性能和加工性能。结果表明:由于特殊的链结构和相对分子质量曲线呈双峰分布的特点,双峰HDPE小中空容器专用树脂力学性能优异,具有高的耐环境应力开裂性。     

聚乙烯中空料耐环境应力性能评价方法探讨

针对聚乙烯中空树脂的耐环境应力试验(吹塑容器法)进行探讨,并应用该方法对八种国内外典型的聚乙烯中空树脂的耐环境应力开裂性能进行评价。还借助密度、结晶度和扫描电镜对结果进行分析,确认该方法能够有效地评价中空树脂的耐环境应力开裂性能。     

聚乙烯耐环境应力性能评价方法的关联性

针对聚乙烯中空树脂耐环境应力性能3种测试方法的关联性进行了探讨。分别采用耐环境应力开裂试验(ESCR法)、拉伸负荷应力开裂试验(切口恒载拉伸法)、耐环境应力开裂试验(吹塑容器法)对8种典型的国内外聚乙烯中空树脂进行了性能评价,并对3种测试方法的测试数据进行对比分析,找出了其间的关联性。从ESCR法和切口恒载拉伸法的数据可看出,2种方法的数据相关性较好。对于聚乙烯大中空树脂,吹塑容器法和ESCR法的F_(50)值整体趋势相同。对于聚乙烯小中空树脂,3种耐环境应力开裂方法没有明显趋势,吹塑容器法和ESCR法数据没有对应关系。     

钛系小中空容器专用HDPE的性能及优化

对比了钛系与铬系小中空专用高密度聚乙烯(HDPE)的力学性能、耐环境应力开裂性能、熔体强度、阻隔性能、相对分子质量及其分布等.结果表明:钛系小中空容器专用HDPE?HD5502TA具有优异的耐环境应力开裂性能、阻隔性能、刚韧平衡性能、食品安全性以及较宽的相对分子质量分布,可替代铬系小中空容器专用树脂应用于食品、药品、日...     

特殊形状小中空容器专用HDPE的开发北大核心

在实验室模拟高密度聚乙烯(HDPE)装置的聚合工艺,研制出特殊形状小中空容器专用HDPE,进行了工业化生产,牌号为5500B,并研究了其性能。结果表明:5500B的熔体流动速率为0.624 g/10 min,密度为0.958 g/cm^3,耐环境应力开裂时间大于25 h,正己烷提取物的质量分数为0.17%,卫生性能达到GB 9691—1988要求,满足用户生产特殊形状小中空容器的需求。     

小中空容器专用双峰HDPE HD5503GA的结构与性能

采用高温凝胶色谱仪、高压毛细流变仪、差示扫描量热仪等分析了国内首个小中空容器专用双峰高密度聚乙烯(HDPE)HD5503GA的结构与性能,并与小中空容器专用进口双峰HDPE及国产单峰HDPE进行了比较。结果表明:HD5503GA具有加工性能好、相对分子质量分布宽、耐环境应力开裂性好及刚性强的特点,其耐环境应力开裂时间是国产单峰HDPE的16.00倍,是进口双峰HDPE的1.75倍,刚性较国产单峰HDPE高57%以上,与进口双峰HDPE相当;与国产单峰HDPE相比,可降低加工温度10～20℃,且制品表面致密,印刷性好,HD5503GA的加工性与进口双峰HDPE接近,更适宜于高腐蚀性及高极性液体的包装。     

特殊形状小中空容器专用HDPE的开发

在实验室模拟高密度聚乙烯(HDPE)装置的聚合工艺,研制出特殊形状小中空容器专用HDPE,进行了工业化生产,牌号为5500B,并研究了其性能。结果表明:5500B的熔体流动速率为0.624 g/10 min,密度为0.958 g/cm~3,耐环境应力开裂时间大于25 h,正己烷提取物的质量分数为0.17%,卫生性能达到GB 9691—1988要求,满足用户生产特殊形状小中空容器的需求。     

2008全球塑料产业最为令人关注的新成果

巴斯夫公司在2008年推出的“明星级”产品当属Ultraform E3120BM新型吹塑级聚甲醛树脂,公司计划将这种树脂于2009年3月实现商业化生产。据BASF介绍,利用Ultraform E3120BM树脂可以实现高效率、低成本地加工具有耐化学品特性、半透明性的中空容器制品。与聚乙烯中空容器相比,用该聚甲醛树脂加工的容器具有更好的阻隔性能。这种树脂在挤出吹塑时,具有非常高的熔体劲度,     

药用塑料瓶设备的基本技术参数与成型工艺

当前至今后一段时间内我国的药用塑料包装容器将是快速发展时期，其中盛装药品片剂，胶囊用的高密度聚乙烯瓶HDPE，聚丙烯瓶（PP），将会取代低质的黄园玻璃瓶的落后包装，规格多在15毫升到150毫升范围内。而药品口服液类塑料瓶在“十五”期间到2010年，其用量将大幅谋产长，规格由100毫升至200毫升，材料主要为聚耐苯二甲酸乙二醇酯（PET），聚碳酸酯（PC）类，产量由“八五”未的30％增加到60％以上。药品包装企业都在抓住目前发展的大好时要，引进或增加国内外的中空容器设备，扩大再生产，来满足药品包装市场的需求，本提供塑料中空容器设备的有关选型参数、合理选择注射吹塑设备生产药用塑料瓶，并在此设备的基础上，制定出适合容器生产的工艺条件。     

关于逆流冷却塔雨区阻力计算的探讨

在逆流式冷却塔的空气阻力计算中,常常忽略了雨区阻力的计算,包括国标规范与高等教育的教科书等权威文献也未提及,根据工业塔的实测,这部分阻力占全塔空气阻力的1/6左右。本文根据冷却塔设计与运行的实践,并结合国内外学者对此的实验研究成果,经分析总结,给出了一个较为系统可行的计算方法,经验证与工业塔实测基本吻合,可供冷却塔设计中参考使用。     

耐高温尼龙聚邻苯二甲酰胺的研究进展

综述了聚邻苯二甲酰胺(PPA)的特性和应用,对部分PPA新品种制备方法及表征测试作了介绍,还介绍了PPA在耐热性、吸水性、尺寸稳定性、耐焊锡性等方面的研究进展。     

Improving the bending and corrosion resistance of an enamel by the addition of β-Si3N4 whiskers

Enamel–metal composite materials with high strength and corrosion resistance are often used for fabricating enameled pressure vessels for pharmaceutical and chemical production. However, the low bending resistance of the enamel can result in the cracking and delamination of the enamel layer, leading to the loss of corrosion resistance of the enameled pressure vessel, which can result in accidents. Here, based on the goal of increasing the bending resistance of the enamel to prolong its service life, the effect of β-Si₃N₄ whiskers on the mechanical properties of enamel was studied by three-point bending tests. The effect of β-Si₃N₄ whiskers on the acid and alkali corrosion resistance of enamel was studied using aqueous H₂SO₄ and NaOH solutions, respectively. A sudden change in the force of an enameled sample under the three-point bending test was used to evaluate the bending resistance of the enamel–metal samples, and can also be used to evaluate the mechanical properties of other comparable materials. With the addition of 0.5 wt% β-Si₃N₄ whiskers, the bending resistance was significantly improved, along with the acid and alkali corrosion resistance. These findings are expected to provide guidance for the design and production of enamel-metal vessels with improved performance that can significantly lengthen the service life of enameled pressure vessels and reduce the occurrence of accidents.     

电阻器专用涂料(Ⅰ)

介绍了电阻涂料底漆、面漆的种类和各类电阻涂料底漆和面漆的组成、特点及技术规格。同时,还简介了环氧型、油墨型及有机硅型标志涂料的特点和技术指标。     

Effect of partial substitution of alumina–chromium slag for Al2O3 on microstructures and properties of Al2O3–SiC–C trough castables

Alumina–chromium slag (ACS), a cheap and abundant refractory raw material comprising aluminum–chromium oxides and β-Al₂O₃, is a byproduct of ferrochrome smelting. For this reason, we investigated the relationships between composition and mechanical properties, abrasion resistance, oxidation resistance, and resistance to iron slag erosion for Al₂O₃–SiC–C trough castables in which ACS was substituted for alumina. Due to the presence of β-Al₂O₃ in ACS, the aluminum-chromium slag reacted with SiO₂ to form a low-melting phase of albite and promoted the formation of mullite, which filled the pores at high temperatures and reduced the porosity, thereby promoting densification and strengthening of the sample. The cold mechanical properties of the sample and the normal temperature wear resistance were enhanced, but the high-temperature mechanical properties and the resistance to iron slag corrosion of the sample were impaired. According to the results of the anti-oxidation experiment, the presence of β-Al₂O₃ in the ACS reduced the porosity and made the sample more dense, which remarkably improved oxidation resistance of the sample. For industrial production requirements, ACS substitution should not exceed 48?wt% due to of thermomechanical properties and anti-slag corrosion performance in Al₂O₃–SiC–C trough castables.     

Enhancement of thermal shock and slag corrosion resistance of MgO–ZrO2 ceramics by doping CeO2

The purpose of this paper was to develop ceramics materials with high thermal shock resistance and corrosion resistance for preparing gas blowing components. In this paper, MgO-rich MgO–ZrO₂ ceramics were obtained by using MgO powder and ZrO₂ powder as starting materials and CeO₂ as an additive. Changes in the properties in terms of thermal shock resistance, mechanical properties, and slag corrosion-resistance with chemical compositions were examined correlated to microstructure and phase changes. Especially, the effect of doping CeO₂ on phase transition of zirconia in MgO-rich system was discussed. The results showed that doping amount of CeO₂ significantly improved properties of MgO–ZrO₂ ceramics. Especially when doping amount of CeO₂ was 2 wt%, residual strength ratio was enhanced over 100% after thermal shock testing. In samples doped with CeO₂, ZrO₂ was stable in cubic or tetragonal form due to complete solution of CeO₂, which was important reason for the improvement of various properties of MgO–ZrO₂ ceramics.     

氧化镁-尖晶石浇注料的组成与性能的关系

以中档烧结镁砂、矾土基尖晶石和电熔白刚玉为主要原料,制备了不同基质组成的试样,并研究了浇注料的流动性、强度、永久线变化率、抗渣性和抗热震性。结果表明：基质的组成（特别是Ａｌ２Ｏ３／ＭｇＯ比）对浇注料的抗渣性、线变化率、抗剥落性和热震稳定性有显著影响,通过调整Ａｌ２Ｏ３／ＭｇＯ比可制得综合性能优良的氧化镁－尖晶石浇注料     

硅树脂及其涂料的研究新进展

综述了近十年来国内外耐热、耐腐蚀、耐候性硅树脂、改性硅树脂及其涂料的研究新进展；指出了硅树脂及其涂料的发展趋势。     

钢骨架塑料复合管的性能和应用

对钢骨架塑料复合管与其他管道的性能进行了比较,对比结果证明:钢骨架塑料复合管具有耐压、耐磨、耐腐蚀、抗蠕变、安装方便以及较高的性价比等特点。     

无醛防皱整理剂的研究进展

传统的防皱整理的发展历程及面临的新问题，阐述了多元羧酸类防皱整理剂作为棉织物理想的无甲醛防皱整理剂的防皱机理及性能，但由于它存在价格贵、织物泛黄色变、耐洗牢度差、含磷催化剂污染环境等问题，需要有效解决。最后，指出了无醛防皱整理今后的发展方向。