Novel nanostructured polyamide 6/fluoroelastomer thermoplastic elastomeric blends: Influence of interaction and morphology on physical properties

Novel polyamide 6 (PA6)/fluoroelastomer nanostructured thermoplastic elastomeric blends were developed in the present work. The influence of interaction between the components and morphology on physical properties of the blends was analyzed. Scanning electron microscopy and atomic force microscopy studies, solubility and theoretical analysis of complex modulus clearly indicated that PA6 was the continuous matrix in which fluorocarbon elastomer was present in nanoscale. Low torque ratio (0.34) of rubber/plastic, high mixing speed and long mixing time had an important role in developing the nanostructured morphology of the blend. Tensile strength of the thermoplastic elastomer was about 39.0 MPa which was much higher than that reported earlier and showed significant improvement with increasing PA6 content. Large shifting of the glass transition temperature of the rubber and the plastic phases towards the lower temperature compared to those pristine polymers was also observed. The above properties were explained with the help of interaction between the components and morphology.     

聚酰胺超细纤维人工麂皮加工的关键技术

从基布的合理选择、非织造布的生产、基布的制造工艺和助剂选择以及最后的染色工艺等方面,详细叙述了聚酰胺超细纤维人工麂皮加工的关键技术.     

Crystalline organization and toughening: example of polyamide-12

Improving the impact resistance of plastics is a key to many applications. Today, dispersing rubber and inorganic particles into semicrystalline polymers is widely used to increase their impact strength without greatly altering other interesting properties such as elastic modulus or chemical resistance. Yet, the underlying mechanisms controlling such toughening are controversial. Hitherto it has been often suggested that a critical distance between particles which controls the brittle-to-tough transition is an intrinsic property of the polymer. On the contrary, we demonstrate here that differences in crystalline organization of the matrix can induce dramatic changes in toughening efficiency. A thermal treatment and microscopic observations strongly suggest that crystalline orientation, size of crystalline grains and molecular organization at grain boundaries play a determinant role in the toughening mechanisms. These observations may have important implications for designing and manufacturing tough plastic materials.     

Preparation and properties of polyamide 6 thermal conductive composites reinforced with fibers

The majority of inorganic particles-filled thermal conductive composites highlight thermal conductivity in detriment of mechanical properties. In this work, magnesium hydroxide (Mg(OH)₂), alumina (Al₂O₃) and flake graphite-filed polyamide 6 (PA6) composites prepared by twin-screw extruder, were reinforced with carbon and glass fibers separately. Effects of fiber type and content on thermal conductivity, mechanical properties and heat deflection temperature (HDT) of the PA6-based composites were investigated. The results showed that the thermal conductivity of the composites improved with increasing carbon fiber content, while decreased slightly with glass fiber loading. Furthermore, strength, modulus and HDT of the PA6-based composites increased with the increase of fiber content. The reinforcing effects of the two fibers on the thermal and mechanical properties of the composites were compared and interpreted in this paper. By incorporating simultaneously high thermal conductive fillers and high-strength fibers, the combined composites hold a good potential in heat dissipation applications.     

Effects of the use of polyamide powder wastes on the microstructure and macroscopic properties of masonry mortars

This study concerns the fabrication of lightweight mortars in which varying quantities of sand were substituted by polyamide powder waste. The values of apparent density, mechanical resistances, permeability, and thermogravimetric analyses are characterised according to the amount of polyamide powder waste used into the mixtures. The microstructure is analysed by Mercury Intrusion Porosimetry (MIP) and by Scanning Electronic Microscopy (SEM). The reconstruction of the mortar macrostructure is completed using Computerized Axial Tomography (CAT). The progressive increase of the amount of polyamide influences the mortar properties, reducing their density and their mechanical resistances and increasing their porosity. These results support the management of polyamide powder waste as a mean to manufacture lightweight masonry mortars.     

导热型高性能树脂微电子封装材料之二:封装材料的导热和热膨胀性能

微电子行业迫切需要新一代优异性能的封装材料。采用聚酰亚胺/氮化铝复合材料作为封装材料,可以组合聚酰亚胺和氮化铝的优点,具有高导热、低热胀、低介电、电绝缘等优异的性能,应用于现代微电子领域前景良好。文章讨论了这种封装材料的导热性能和热膨胀性能。PMR聚酰亚胺/氮化铝复合封装材料导热系数随氧化铝的加入量而显著提高,Bruggeman方程最适合于描述该封装材料的导热系数。PMR聚酰亚胺与氮化铝复合后热膨胀系数显著减小。     

织物用聚酯酰胺热熔胶的研制

研究了以聚酯胶和聚酰胺胶为原料在催化剂的作用下加热共熔,通过大分子链交换反应制备织物用聚酯酰胺热熔胶的方法。用聚酯胶的溶剂对所得产品进行溶取试验并且通过红外光谱分析都证明了链交换反应的存在。用该法所得产品粘接强度大,既耐水洗又耐干洗,适用于粘合衬生产。     

The influence of structural properties on the dye diffusion and dyeabilty of PA 6 fibres

The relationships were investigated between the structural and dyeing properties of different structurally modified PA 6 fibers. PA 6 monofilament yarn samples were applied having different crystalline degrees and different content of alpha, respectively gamma crystalline modification. The diffusion coefficients of two different acid dyes were determined together with the content of dyestuff absorbed (under specific conditions) by fiber samples. In order to estimate colorimetry method from the viewpoint of polymer structural change detection, the colors of the dyed PA 6 samples were determined (L*, a*, b*, C*, h coordinates) and the color differences (L*, a*, b*, C*, H*, E*) were calculated between untreated standard and structurally modified samples. The dyeability of PA 6 fibers depended mainly on the way in which crystallinity had been achieved, i.e. on the material's history. Different crystalline modifications caused different sorption properties and fiber dyeability. Smaller increases (app 20%) of crystallinity degree caused a decrease in diffusion coefficients. Contrary to expectations, the significant increase of crystallinity degree (app 50%) had an influence on the increase of dyeability, presumably owing to the formation of larger empty spaces in the structure. The results achieved by colorimetry were in good correlation with dye absorption measurements. The colorimetry of dyed fiber samples was sensitive enough to detect even small differences in the quantities of absorbed dyestuff.     

聚酰胺合金研究进展

介绍了聚酰胺合金的开发现状、相容化技术、主要性能及应用领域。探讨了聚酰胺合金今后的发展趋势。     

复合固化剂在环氧胶粘剂中的应用

本文介绍了环氧树脂胶粘剂在实际应用中采用复合固化剂的方法,在不同温度条件下,调整两种固化剂的比例,获得较好的粘接效果。