聚合MDI中二环化合物含量对发泡性能的影响

制备了不同2，4’-MDI含量、不同二环化合物含量的聚合MDI样品，分别与以CFC-1l和环戊烷为发泡剂的组合聚醚进行了发泡实验，考察了其流动性和脱模性能与组成的关系。实验结果表明，当聚合MDI与2种组合聚醚进行发泡时，2，4’-MDI含量对聚合MDI的发泡流动性影响较小，而对后熟化性能的影响明显，随2，4’-MDI含量的增加，脱模变形呈直线上升的趋势。与此对应，无论是CFC-1l型组合聚醚还是环戊烷型组合聚醚，二环化合物含量对聚合MDI的发泡流动性能和后熟化性能影响很大，是影响聚合MDI应用性能的关键因素。二环化合物含量的增加，可以显著地提高泡沫的发泡高度指数、降低密度分布系数，改善聚合MDI的发泡流动性能，但泡沫的脱模变形量增大，后熟化性能明显变差。     

Preparation and properties of MDI/H12MDI‐based water‐borne poly(urethane‐urea)s—Effects of MDI content and radiant exposure

Water‐borne poly(urethane‐urea)s (WBPUs) were prepared by a prepolymer mixing process using aromatic diisocyanate (MDI, 4,4′‐diphenylmethane diisocyanate)/aliphatic diisocyanate (H₁₂MDI, 4,4′‐methylenebis cyclohexyl isocyanate), polypropylene glycol (PPG, M_n = 1000), dimethylol propionic acid, and ethylene diamine as a chain extender, and triethylamine as a neutralizing agent. The effect of MDI on the molecular weight, chemical structure, dynamic thermo, and tensile properties of WBPUs was investigated. The yellowness index (YI, photo‐oxidation behavior) change of WBPUs under accelerated weathering exposure was also investigated. The WBPUs containing higher MDI content showed lower molecular weight, which verified the participation of some high reactive isocyanate groups of MDI into side reaction instead of chain growing reaction. As the MDI content increased, the storage modulus and tensile modulus/strength of WBPUs film increased, and their glass transitions of soft segments (T_gs) and hard segments (T_gh) were shifted to higher temperature. The intensity of tan δ peak of all three samples increased with increasing radiant exposure. The YI of H₁₂MDI‐based WBPU sample (WBPU‐0) was not occurred. The YI of WBPUs containing MDI increased with increasing MDI content and radiant exposure. However, the YI of sample WBPU‐25 containing 25 mol % of MDI at 11.3 MJ/m² (radiant exposure) was 6.6 which is a permissible level for exterior applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

基于多协议层QoS参数关联的IPTV故障点定位方法

首先对IPTV马赛克、卡片等视频业务质量问题的原因进行深入分析,并与现有常用的IPTV监测方案对比,提出了一种创新的基于MPEG-TS层和RTP层QoS参数关联的IPTV业务质量分析与故障点定位方法.运维实践表明,该方法实施简便、经济有效,具有较强的推广价值.     

MDI生产高性能环保型聚氨酯防水涂料的研制

以MDI和DL2000为主要原料,通过正交实验,获得了制备高性能环保型聚氨酯防水涂料的最佳工艺条件;并添加固体填料膨润土,分析其对涂膜性能的影响。最后进行了红外光谱、热重分析和其他综合性能等测试。实验结果表明:制备高性能环保型聚氨酯防水涂料的最佳工艺条件为MDI和DL2000的最佳配比NCO/OH=2:1(物质的量之比,下同),交联剂3%(质量分数,下同),催化剂2%,反应温度60℃,反应时间70min;膨润土的最佳添加量为4%,并且提高了涂膜的热稳定性;制备的防水涂料具有较高的力学强度,良好的附着力、较低的吸水率、较好的热稳定性和耐酸碱性能。     

浇注型聚氨酯弹性体耐酸碱性能研究

以不同种类二异氰酸酯和各种多元醇为主要原料,通过预聚法合成了一系列结构不同的聚氨酯弹性体(PUE),研究了软硬链段的化学结构及硬段含量对PUE耐酸碱性能的影响。结果表明,聚四氢呋喃醚多元醇作为软段具有更加稳定的化学结构,有利于PUE耐酸碱性的提高。选用刚性较大的二异氰酸酯4,4’-二苯基甲烷二异氰酸酯(MDI-100),以刚性对称的氢醌-双(β-羟乙基)醚(HQEE)为扩链剂,有利于聚氨酯分子链硬段的规整排列从而产生结晶,可提高PUE的耐酸碱性。     

Effect of Poly(dimethylsiloxane) Content on the Properties of Water-Borne Poly(urethane-urea)s Containing MDI

Low photo- and water-resistance is often cited as the problem of MDI-based WBPU. This study addressed this problem. Water-borne poly(urethane-urea)s (WBPUs) were synthesized using a pre-polymer mixing process from 4,4'-methylenebis(phenyl isocyanate)(MDI)/4,4-dicyclohexylmethyl diisocyanate (H₁₂MDI) (15/85 mole %)/dimethylol propionic acid (DMPA)/ethylene diamine (EDA)/triethylamine (TEA) with different poly(propylene glycol) (PPG, M _n = 2000)/hydroxyl terminated poly(dimethylsiloxane) (PDMS, M _n = ～550) molar ratios. This study highlights the effect of PDMS content on the inherent viscosity, hydrogen-bonding, storage modulus, tan δ peak intensity, tensile modulus/strength, elongation (%) at break, water swelling (%), contact angle, and the yellowness index of WBPUs containing MDI. The mechanical properties (strength/modulus), water-resistance and photo-resistance of WBPUs containing MDI increased significantly in proportion to the PDMS content. These results indicate the potential for using multi-performance WBPU with PDPS for WBPU coatings.     

中密度纤维板工厂作业环境空气中的MDI检测

I-BOND是基于聚合MDI制成的胶黏剂,在木材行业中大量使用.对欧洲17家中密度纤维板厂在生产期间测得数据表明.存使用I-BOND生产中密度纤维板期间,工作环境中测得的MDI接触水平多数较低,而且低于相关国家制定的职业接触限值.     

棉纺工艺计算机辅助设计软件开发初探

为促进计算机技术在棉纺工艺设计中的应用,运用Delphi7程序设计语言和ADO技术,采用MDI窗体模式开发了基于Windows操作环境的棉纺工艺计算机辅助设计软件.指出:棉纺工艺计算机辅助设计软件有助于消除工艺人员长期以来通过手工计算、查阅资料等传统工艺设计方式所存在的弊端,提高棉纺工艺设计的效率和准确性.经初步试用效果良好.     

二苯基甲烷二异氰酸酯精馏过程节能工艺研究

为了开发二苯基甲烷二异氰酸酯(MDI)分离的节能流程,采用热平衡法和有效能分析法,对MDI精馏过程进行节能研究,从单个换热过程到整个系统分3个步骤进行改进。首先改变脱光气塔和减压脱溶剂塔的用能品位,节省高品位热源;然后通过回收各个子系统的冷凝热和冷却热,实现单元内部的能量再利用;最后通过常压脱溶剂塔与脱光气塔的热量集成,使得能耗进一步降低。通过以上3个过程的节能改进,得到的工艺流程同原工艺相比节能30%以上。给出的节能方法适用于MDI分离过程,也可应用于类似的宽沸程物系的分离过程。     

MDI在商业MIS框架生成系统中的应用

本文介绍了多文档界面（ＭＤＩ）在商业ＭＩＳ框架生成系统（ＦＧＳＭ）中的应用。重点介绍了ＦＧＳＭ系统程序框架结构及其实现的关键技术。