Effect of β-irradiation on mechanical properties of metallocene elastomers/PA6 blends

Binary blends of metallocene polymers with polyamide-6 as dispersed phase and ternary blends with a metallocene-grafted rubber as compatibilizer were prepared and treated by electron beam radiation. Thermal stability and mechanical properties were studied, showing that thermosetting rubbers and thermoplastic elastomers with excellent mechanical properties and thermal stability may be obtained by β-irradiation. The irradiated ternary blends displayed high break elongation values, similar to other thermoplastic rubbers based on EPDM or EPR materials. On the other hand, the Shore D hardness, tensile strength, high-temperature behavior, compression set and reprocessing ability were found to be clearly dependent on the metallocene polymer used as bulk phase and the irradiation dose employed.     

Thermal and crystalline behaviour of silk fiborin/nylon 66 blend films

A series of blend films of silk fibroin (SF) with nylon 66 were prepared by the common solution cast method. DSC analysis of every blend sample showed a large and broad endothermic peak around 150 °C. For SF/nylon 66 samples containing 10 and 30 wt% SF, large spherulites were observed and their melting processes were recorded using a polarizing microscope with hot-stage. Furthermore, a detailed study on 30 wt% SF sample indicated a distribution of two distinct spherulites: large spherulites in part A and much smaller ones in part B. In WAXD pattern, the large spherulites presented new peaks different from nylon 66 or silk's characteristic peaks that were ever reported, while the small ones assumed triclinic form of normal nylon 66. SEM showed that the SF and nylon 66 were nearly miscible in all ratios except that of 50 wt% SF.     

Effects of annealing (solid and melt) on the time evolution of polymorphic structure of PA6/silicate nanocomposites

The effects of annealing including solid-state annealing (190 °C) and melt-state annealing (230 and 250 °C) on the polymorphic behavior and thermal property of polyamide 6 (PA6)/layered-silicate nanocomposites (PA6LSN) have been investigated as a function of annealing time using Modulated Differential Scanning Calorimetry (MDSC) and wide angle X-ray diffraction. For comparison, thermal behavior and polymorphism of pure PA6 were also studied. It was demonstrated that PA6LSN and PA6 exhibited a similar polymorphic behavior when they were annealed in the solid state for different time duration. As the annealing temperature was elevated to 230 and 250 °C, significant differences in thermal behavior and polymorphism between PA6LSN and PA6 could be found. For example, the γ phase became the absolutely dominating for PA6LSN, while the α crystal was the most predominant phase in neat PA6. Moreover, a new endothermic peak is observed around 235 °C in all PA6LSN MDSC scans, which might be related to the melting of PA6 lamellae formed in the confined environment on the surface of the nano-silicate.     

Super-toughening polyamide-612 by controlling dispersed phase domain size: Essential work of fracture assessment

A new pathway to super-toughen polyamide-612 (PA-612) by incorporating domains of soft poly(octene-co-ethylene)-g-maleic anhydride (POE-g-MA) via melt blending leading to more than ∼1100% increase in notched Izod impact strength vis-à-vis fracture toughness enhancement is demonstrated. Fourier transform infra red (FTIR) studies showed effective phase interactions between PA-612 and POE-g-MA whereas dynamic mechanical analysis (DMA) revealed a reduction in loss-peak intensity at ∼45 °C with increase in the soft phase fraction. The optimal dependence of fracture-toughness (in plane-stress) on domain-size (D_n) of dispersed-phase in the form of a reduction in resistance to crack initiation indicated by essential work of fracture (w_e) and linear increase in resistance to crack propagation indicated by non-essential work of fracture (βw_p) of the blends ⩾10 wt% of POE-g-MA content is correlated to an increase in domain-size ⩾∼0.3 μm. Fracture surface morphology indicated crazing to be responsible for the transition in fracture behavior, i.e. remarkable toughening of PA-612 at the critical rubber phase domain size range of ∼0.2–0.3 μm.     

锦纶空气变形丝织物的生产技术要点

总结锦纶空气变形丝织物的生产技术要点。通过介绍176dtex/96F全消光锦纶空气变形丝的性能指标,在整经工序中避免过度牵伸,保证张力一致,整经速度300m/min;浆纱工序使用锦纶专用浆,以贴伏毛圈减磨为主,上浆率掌握在3.2%为宜;并轴工序注意各浆轴的退解张力一致,设定锥形卷绕比例为5%;喷水织造工序增加开口量,注意各工艺角度的配合。通过以上工艺措施的实施,织机效率达到92%以上,一等品率达到88%,产品的质量稳定。认为:根据锦纶空气变形丝的特性优化各工序工艺参数可以保证产品的顺利生产。     

锦棉混纺织物色底迷彩织物染整工艺探讨

介绍锦棉混纺织物色底迷彩服面料的染整加工工艺,包括染料的优选、染色工艺的确定,以及生产中操作注意点。     

减少尼龙织物染色大小样色差

染色大小样之间的色差一直是困扰染色生产的一大问题,本文以尼龙织物染色为例,从染料、助剂、设备的使用及染色工艺等几方面,具体探讨如何减少尼龙织物染色大小样的色差。     

Combination of Plasma Functionalization and Phase Inversion Process Techniques for Efficient Dispersion of MWCNTs in Polyamide 6: Assessment through Morphological,Electrical, Rheological and Thermal Properties

Different contents of multiwalled carbon nanotube (MWCNTs) functionalized by He-dielectric barrier discharge (DBD) plasma followed by an exposure to NH₃ were incorporated into PA6 matrix via a phase inversion based solution method. Optical and electron microscopic results were indicative of the excellent dispersion state of the MWCNTs. The differential scanning calorimetry and thermogravimetric analysis measurements revealed that even addition of a slight amount of the MWCNTs significantly increased the thermal stability and crystallization temperature. Moreover, the low electrical percolation threshold of the PA 6/functionalized MWCNTs nanocomposites was another confirmation for achieving a good dispersion state of MWCNTs using this approach.     

Surface properties of polyamides modified with reactive polydimethylsiloxane oligomers and copolymers

Surface modification of polyamide-6 (PA-6) was investigated by melt blending with silicone-urea copolymers or organofunctionally terminated polydimethylsiloxane oligomers. Blends were prepared in a laboratory scale high-shear melt mixer. Surface characteristics of the blends were determined by static water contact angle measurements and X-ray photoelectron spectroscopy. Effect of the type, composition, average molecular weight and amount of the silicone additive in the blends, on the surface properties were determined. Influence of the thermal history of the samples on the surface properties was also investigated. All of the blends showed formation of silicone rich surfaces. Surface modification was permanent due to either the formation of chemical bonds between additive and polyamide and/or very strong hydrogen bonding between urea and amide groups.     

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。