N-羟甲基丙烯酰胺对纸张涂层剂性能的影响

研究了 N-羟甲基丙烯酰胺 ( NMA)对 VAc-BA-NMA三元共聚物乳液用作纸张涂层剂性能的影响。     

烧结法制备微晶玻璃材料

微晶玻璃是由玻璃原位析晶而获得的一种结构均匀，致密，晶粒尺寸为纳米或亚微米级的新型陶瓷复合材料。本文介绍了烧结法制备徽晶玻璃复合材料的特征、工艺原理、微观结构、性能及应用。     

Effects of Poly(ϵ-caprolactone) on Structure and Properties of Poly(lactic acid)/Poly(ϵ-caprolactone) Meltblown Nonwoven

To obtain flexile poly(lactic acid)-based melt-blown nonwoven filtration material, poly(lactic acid)/poly(?-caprolactone) melt-blown nonwoven with various components were melt-spun by melt-blown processing in the Melt-blown Experiment Line. The 3 wt.% tributyl citrate to poly(?-caprolactone) was added in the composites as compatibilizer. The effect of poly(?-caprolactone) on the structure, morphology, mechanical and filtration properties of poly(lactic acid)/poly(?-caprolactone) melt-blown nonwoven was reported. Scanning electron microscopy micrographs revealed good dispersion of the additive in the fiber webs. The crystallinity of melt-blown webs with poly(?-caprolactone) was more than that of poly(lactic acid) alone. The tensile strength, ductility and air permeability of poly(lactic acid) melt-blown nonwovens were enhanced significantly. The input of poly(?-caprolactone) increased the diameter of fibers and decreased the filtration efficiency of poly(lactic acid)/poly(?-caprolactone) melt-blown nonwoven.     

硬沥青改性聚苯乙烯材料的研究

采用熔融共混方法,用深度萃取脱油硬沥青和尤里卡沥青两种高软化点硬沥青材料,对聚苯乙烯(PS)进行改性。力学性能测试表明,硬沥青材料的加入能使PS的冲击强度得到不同程度的提高,但拉伸强度有一定程度下降;透射电镜微观证实,硬沥青在聚苯乙烯材料内主要以约100nm的微粒分布,均匀分散的硬沥青超胶束引起的锚钉效应是聚苯乙烯材料冲击强度提高的原因,但胶束及似晶结构不能有效分散开,导致其拉伸强度等得不到提高。     

VTMS/MMA/St三元共聚物的合成与表征

以甲基丙烯酸甲酯（MMA）、苯乙烯（St）、乙烯基三甲氧基硅烷（VTMS）为单体通过乳液聚合制备了含有机硅氧烷的三元共聚物乳液;研究了单体配比与转化率之间的关系．并表征了共聚物的结构,测试了共聚物的热性能。结果表明,共聚物中成功地引入丁有机硅链节．聚合过程中部分硅氧烷部分发生水解,共聚物的热稳定性和玻璃化温度有一定提高。     

柔性成膜剂和附加剪切场对GF/PP结构与性能的影响

利用自制的可控剪切应力场装置,连接在熔融挤出机料筒末端,使复合材料熔体在成型过程中,受到可控的附加剪切应力场作用,试验成膜剂和附加剪切场对玻纤增强PP复合材料界面结构与性能的作用。结果表明:在成型加工过程中,附加剪切场会改变GF/PP复合材料界面结构,其变化程度与玻纤处理工艺有关,柔性成膜剂有稳定复合材料界面结构和提高GF/PP复合材料力学强度的作用;在所用3种成膜剂中,POE效果最佳,PUR其次,K树脂较差。     

Targeting optimum resource allocation using reverse problem formulations and property clustering techniques

Decoupling the constitutive equations from the balance and constraint equations allows for reformulating a conventional forward problem into two reverse problems. The first reverse problem is the reverse of a simulation problem, where the process model is solved in terms of the constitutive (synthesis/design) variables instead of the process variables, thus providing the synthesis/design targets. The second reverse problem (reverse property prediction) solves the constitutive equations to identify unit operations, operating conditions and/or products by matching the synthesis/design targets. Visualization of the problem is achieved by employing recently developed property clustering techniques, which allows a high-dimensional problem to be visualized in two or three dimensions. The clusters by definition satisfy intra-stream and inter-stream conservation through linear “mixing” rules, which allows for the development of consistent additive rules along with their ternary representation.     

PET/PA66共混体系的流变性质与形态结构的关系

采用溶液法、熔融法Ⅰ(简单机械共混)和熔融法Ⅱ(存在酯—酰胺交换反应)共混,将聚对苯二甲酸乙二酯(PET)与聚酰胺66(PA66)共混。用Instron 3211型毛细管流变仪和扫描电镜研究了共混体的流变性能和形态结构.结果表明,PET/PA66共混体熔体为切力变稀流体,其行为遵守幂律方程,η(?)C_(pass)(wt.％)曲线表明该共混体为一负偏差体系,当PA66含量为25％左右时,负偏差最大。不同共混方式所制得的共混物形态结构的差异是造成共混物流变性能差异的直接原因。     

CNT-MF/硅橡胶泡沫复合材料的制备及介电性能

以碳纳米管(CNT)作为核,密胺树脂(MF)作为壳,苯乙烯马来酸酐共聚物(SMA)为乳化剂,原位聚合制备微胶囊化碳纳米管(CNT-MF),并将包覆后的碳纳米管作为填料添加到硅橡胶泡沫中,制备了CNT-MF/硅橡胶泡沫复合材料。探讨了核/壳质量比对微胶囊化碳纳米管的包覆效果的影响,同时研究了微胶囊化碳纳米管用量对硅橡胶泡沫泡孔结构和介电性能的影响。结果表明,微胶囊化碳纳米管的加入有利于提高复合材料的泡孔结构,大泡孔的存在和泡孔面积有利于材料介电性能的提高。当核/壳质量比为1∶10的微胶囊化碳纳米管添加量为15 phr时,复合材料介电性能表现最佳,此时复合材料在1 kHz的介电常数为26.34,介电损耗仅为0.013 6。     

Effect of zirconia particle size on the properties of alumina-spinel castables

The industrial application of alumina-spinel refractory castables has crucial requirements on the service performance. Thus, the effects of different sized desilicated zirconia particles on the castables microstructure, thermal-mechanical properties and high temperature elastic modulus have been investigated. The zirconia particle sizes were varied from 1000 µm to 2.5 µm (d₅₀). It was observed that the finer (below 88 µm) zirconia particles were beneficial to improve the cold modulus of rupture (CMOR) and the hot modulus of rupture (HMOR), but could not effectively enhance the thermal shock resistance. Fine zirconia particles can homogeneously disperse in the matrix and significantly promote the sintering process. Accompanied with the phase transformation of zirconia, both the high density of matrix cracks and the strong ceramic bonding (between the coarse grains and the matrix) were found in the refractory castables, which was responsible for an increase of CMOR. However, the binding characteristic could also give rise to the high stored elastic energy that was adverse to the thermal shock resistance, and the excessive amount of preexisting matrix cracks could induce more microdamage during the thermal shock. Additionally, it was proposed that the second-phase dispersion reinforcement and the highly ceramics bonding resulted in the superior HMOR when introducing fine ZrO₂ particles.