Amide–acid functional SiO2 nanocomposites based on new semi‐crystalline poly(ether‐sulfone‐amide): thermal,combustion and mechanical studies

New amide–acid functional SiO₂ nanoparticle (FSNP)‐reinforced semi‐crystalline aliphatic–aromatic poly(ether‐sulfone‐amide) (PESA) was synthesized using a solution method in dimethylformamide. The surfaces of SiO₂ nanoparticles were functionalized with phthalic anhydride, and subsequently PESA was synthesized using direct polymerization with good yield and desired molar mass. PESA / SiO₂ nanocomposites (PSNCs) were prepared with three different contents of FSNP and the morphology and mechanical, thermal and combustion properties of the PSNCs were studied. The results of X‐ray diffraction, field‐emission scanning electron microscopy and transmission electron microscopy showed a uniform dispersion for FSNP in the PESA matrix. According to the results of mechanical tests, the tensile strength and the Young's modulus of PESA were enhanced by FSNP loading. Thermogravimetric analysis and derivative thermogravimetry results showed a substantial improvement in thermal properties of PESA. The temperature at 5% mass loss was increased from 371.7 to 395.8 °C for the PSNC containing 8 mass% of FSNP, as well as the char yield being enhanced greatly, which was about 30% higher than that of neat PESA. Significant improvements in combustion properties were observed for PSNCs from microscale combustion calorimetry. The peak heat release rate showed an obvious improvement and decreased by about 57% compared to that of neat PESA on 8 mass% loading of FSNP. © 2016 Society of Chemical Industry     

Structure–property relations of nylon‐6 and polytetramethylene glycol based multiblock copolymers with microphase separation prepared through reactive processing

A series of poly(urethane‐urea‐amide) thermoplastic elastomers (PUUAs) based on polytetrahydrofuran (polytetramethylene glycol, PTMG), nylon‐6 and 4,4′‐diphenylmethane diisocyanate were synthesized through reactive processing. This method solved the incompatibility of nylon‐6 and PTMG, and these model elastomers were used to gain insight into the structure–property relations of block polymers. The target products were solvent resistant, transparent and melting‐processable. Fourier transform infrared spectroscopy, XRD, DSC, TEM, dynamic mechanical analysis, tensile testing and TGA were used to study the structure, crystallization, morphology, mechanical properties and thermostability of the PUUAs. The Fourier transform infrared results proved the successful preparation of PUUAs from nylon‐6 and PTMG. TEM examination showed that all samples exhibit microphase separated morphology with the nylon‐6 domain dispersed in the PTMG phase. The results of tensile testing indicated that the elastomers exhibit excellent mechanical properties with stress at break and strain at break exceeding 40 MPa and 600% respectively. The TGA results implied that the PUUAs can be fabricated by transitional processing at proper temperature without any thermodegradation. These favorable features were related to the microphase separated structure of the PUUAs. © 2016 Society of Chemical Industry     

Gasoline permeation resistance of the as‐blow‐molded and annealed polyethylene,polyethylene/polyamide,and polyethylene/modified polyamide bottles

An investigation of the gasoline permeation resistance of the as‐blow‐molded and annealed polyethylene, polyethylene (PE)/polyamide (PA), and polyethylene/modified polyamide (MPA) bottles is reported. The gasoline permeation resistance improves dramatically after blending PA and MPA barrier resins in PE matrices during blow‐molding, and the order of barrier improvement corresponds to the order of barrier improvement of the barrier resins added in PE. Somewhat unexpectedly, the gasoline permeation rates of the annealed PE and/or PE/PA bottles annealed at 90°C or higher temperatures increase significantly with the annealing temperature and time. On the contrary, the gasoline permeation resistance of the annealed PE/MPA bottles increase significantly as the annealing temperature and/or time increase. For instance, the gasoline permeation rate of the PE/MPA bottle annealed at 120°C for 32 h is about 190 times slower than that of the as‐blow‐molded PE bottle. Further investigations found that, after blending the MPA and PA barrier resins in PE matrices, the relatively nonpolar hydrocarbon components present in the gasoline fuels were significantly blocked, without permeation during the permeation tests, in which the as‐blow‐molded PE/MPA bottle inhibited the permeation of hydrocarbon components more successfully than did the as‐blow‐molded PE/PA bottle. In contrast, the amounts of polar components that permeated through the as‐blow‐molded PE/PA and PE/MPA bottles were very small and about the same as the amount that permeated through the as‐blow‐molded PE bottle. Possible mechanisms accounting for these interesting behaviors are proposed in this study. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2827–2837, 2001     

Synthesis,spectral properties,and application of 1,8‐naphthalimide fluorophores for modified polymers

The presence of the epoxy group in the structure of 1,8‐naphthalimide fluorophores opens up possibilities to prepare compounds with new valued properties through covalent bonding to both polyamide and epoxy oligomers. Two new 4‐(1‐amino‐2,3‐epoxypropyl)‐9‐substituted‐1,8‐naphthalimides were synthesized, and their absorption and fluorescence characteristics were determined. The introduction of the substituent contributes to both the yellow color and strong fluorescence of the compounds, the quantum yield being about 0.9. The possibility for structural coloration of polyamide textile materials and epoxy oligomers has been investigated. The modified polymers are with intense green fluorescence, possessing a strong resistance to various physico‐chemical treatments and light. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1863–1869, 2001     

石油发酵尼龙1012的合成及表征

用石油发酵方法制的十炭二元胺和十二碳了酸合成了石油发酵尼龙１０１２。红外光谱测定表明合成产物确为尼龙１０１２。测定了此经龙１０１２，测定了此种尼龙１０１２的物理力学性能和相对粘度，结果表明，石油发酵尼龙１０１２是一种性能优良的新型工程塑料。     

Grafting of poly(acrylic acid) on polyamide yarn

Graft copolymerization of acrylic acid onto PA6 yarn was examined in this study. Prior to the grafting process, the fibers were activated with a benzene solution of benzoyl peroxide. Next, the fibers were put into a bath containing acrylic acid, a dispersing agent, and the activator of reaction. The effects of the main process parameters and auxiliary additives on the degree of grafting, quantity of the homopolymer formed during grafting, effectiveness of grafting, extent of conversion, and grafting ratio were determined. Using calculation factors such as the reaction efficiency, the extent of reaction, and the ratio of grafting, the conditions of grafting were found that made possible the reduction or elimination of the by‐product. Also determined were the influence of the degree of grafting on the moisture sorption and the swelling of modified fibers. In addition, the value of apparent activation energy was calculated (49.123 kJ/mol). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1914–1919, 2001     

尼龙无纺布增韧RTM复合材料的湿热老化性能

采用尼龙无纺布(PNF)作为结构化增韧层,利用树脂传递模塑(RTM)工艺制备了PNF层间增韧改性的碳纤维增强环氧树脂基复合材料(U3160-PNF/3266),研究了U3160-PNF/3266复合材料的吸湿特性及湿热老化对其耐热性能的影响。结果表明:增韧前后复合材料具有相似的吸湿动力学特性,但在吸湿初期,U3160-PNF/3266复合材料具有更大的吸湿速率,达到饱和吸湿后,U3160-PNF/3266复合材料的饱和吸湿率约为0.96%,略大于非增韧复合材料U3160/3266的0.87%。随着湿热老化时间的增加,两种复合材料的玻璃化转变温度均逐渐降低,并随着吸湿率的饱和而趋于平稳,达到饱和吸湿后,U3160-PNF/3266和U3160/3266复合材料的玻璃化转变温度分别下降了约15%和14%。     

Synthesis and properties of polyamide/LLDPE composites with compatibilizer used as hot melt adhesive

In this work, a new polyamide (PA155) was synthesized from higher purity dimer acid, sebacic acid, ethylenediamine, and piperazine, and the ternary blends were prepared by blending PA155 with LLDPE in the presence of the compatibilizer, maleic anhydride grafted linear low-density polyethylene (LLDPE-g-MAH). The weight ratio of PA155 to LLDPE of the samples was kept constant at 80/20 and the amount of LLDPE-g-MAH was varied at 0, 3, 6, 9, and 12 wt% over the total weight of the blend respectively. The scanning electron microscope and mechanical properties tests showed that the compatibility and the mechanical properties were improved with the increase in LLDPE-g-MAH content, and the blend containing 9.0 wt% LLDPE-g-MAH exhibits an optimal miscibility behavior and mechanical properties. The hot melt adhesives which were prepared from the ternary blends were assessed by 180°peel tests of Al/adhesive/polypropylene stack. The peeling strength for the sample containing 9.0 wt% compatibilizer (82.5 N/2.5 cm) is much more than that of the samples without compatibilizer (<20 N/2.5 cm).     

酚醛树脂基新戊二醇磷酸酯阻燃剂的合成及其性能研究

通过用新戊二醇磷酰氯对线型酚醛树脂(PF)酚羟基实行磷酰化封端处理,制备了线型PF基新戊二醇磷酸酯(NDMPP)阻燃剂,将其应用于阻燃PA6。采用核磁共振氢谱(1H NMR)、核磁共振磷谱(31P NMR)和傅立叶变换红外光谱(FTIR)表征了NDMPP的结构,采用热重(TG)分析研究其热分解行为,采用极限氧指数(LOI)和UL 94测试其阻燃PA6材料的阻燃性能,采用万能材料试验机和冲击试验机测试阻燃材料的力学性能。1H NMR,31P NMR和FTIR结果表明,线型PF中大约82%的羟基被磷酰化,NDMPP中的磷含量约为11.9%。TG分析结果表明,NDMPP阻燃剂在氮气气氛下起始分解温度超过250℃,600℃的残炭率达到43.5%,显示出良好的热稳定性。当NDMPP质量分数为25%时,其阻燃的PA6达到UL 94 V–0等级,LOI达到33.4%,而拉伸强度、缺口冲击强度、弯曲强度和弯曲弹性模量分别为纯PA6的76%,41%,72%和71%。     

MCPA6/埃洛石纳米管复合材料性能研究

以氢氧化钠为催化剂,N–乙酰己内酰胺为活化剂,原位聚合制备MCPA6/埃洛石纳米管(MCPA6/HNT)复合材料,并利用凝胶渗透色谱、场发射扫描电子显微镜、差示扫描量热、热重分析和力学性能测试等方法研究HNT用量对复合材料结构和性能的影响。结果表明,HNT的引入使得PA6的分子量下降,分子量分布变宽;经硅烷偶联剂(KH–550)处理后的HNT能均匀分布在MCPA6中,且与基体具有较好的界面性能;HNT可以明显提高复合材料的结晶速率、结晶度以及分解温度;随着HNT含量增加,体系的拉伸强度和缺口冲击强度呈先增大后减小的趋势,而断裂伸长率逐渐下降,当HNT含量为1.5%时,MCPA6/HNT的综合力学性能最佳,拉伸强度和缺口冲击强度分别较MCPA6提高21.3%和14.9%。