微卤阻燃LDPE的研究

研究了氢氧化铝、氢氧化镁和红磷等对低密度聚乙烯(LDPE)阻燃性能、力学性能和成型加工性能的影响。结果表明:氢氧化铝、氢氧化镁和红磷等阻燃剂(经表面改性或细化处理)与LDPE树脂具有较好的相容性,表现出良好的阻燃效果;随着阻燃剂用量的增加,LDPE的阻燃性能明显提高,但其力学性能和加工性能则逐渐下降。当复合阻燃剂氢氧化铝/氢氧化镁/红磷的质量比为50/25/6时,其对LDPE可产生良好的协同阻燃效果。     

氢氧化镁晶须对LDPE阻燃性能的影响

从阻燃剂对LDPE(低密度聚乙烯)的阻燃机理出发,以氢氧化镁晶须为阻燃剂,与低密度聚乙烯进行复合,考察了偶联剂、阻燃剂表面处理、晶须含量等对复合材料力学性能、加工性能、热稳定性、燃烧性能等的影响、并对加工工艺对晶须形态及复合材料性能的影响进行了探讨,以期得到具有良好力学性能和阻燃性能的复合材料,为实际生产提供理论依据。     

茂金属聚乙烯的阻燃改性研究

分别以氢氧化镁和水滑石为阻燃剂,加入到茂金属聚乙烯(MPE)基体中,通过开炼共混、模压成型对MPE进行阻燃改性.研究了氢氧化镁的粒径大小对材料力学和阻燃性能的影响以及氢氧化铁和水滑石在MPE基体中阻燃效果的差异.同时还比较了两种不同醋酸乙烯基(VA)含量的乙烯醋酸乙烯共聚物(EVA)对MPE的力学性能的影响.结果表明:氢氧化镁的粒径大小只影响材料的力学性能,几乎与材料的阻燃性能无关.水滑石特有的结构使其具有比氢氧化镁更优越的阻燃性能.EVA的引入能增强MPE的断裂伸长率,经比较EVA2805(VA含量28%)的综合性能优于EVA4055(VA含量40%).     

炭黑在超高分子量聚乙烯阻燃改性中的作用

介绍了利用炭黑和胶囊化红磷作为阻燃剂对超高分子量聚乙烯(UHMWPE)进行共混改性的研究,比较了不同种类炭黑的作用效果.研究了改性对UHMWPE阻燃性能、力学性能和耐热性能的影响,优化了阻燃配方,讨论了阻燃机理.     

辐照法制备无卤阻燃HDPE/EPDM/硅橡胶共混物

以氢氧化镁和红磷为阻燃剂,硅橡胶、三元乙丙橡胶(EPDM)为共混材料,高密度聚乙烯(HDPE)为基体制备了阻燃共混物,并对其进行电子束辐照,考察了阻燃共混物的力学性能、阻燃性能和微观形貌。结果表明:EPDM的加入明显改善了阻燃共混物的力学性能;硅橡胶的加入使得无机阻燃剂粒子在聚合物基体中的分散性提高,阻燃共混物的氧指(数OI)提高;辐照交联后,阻燃共混物的拉伸强度增强,OI明显提高,燃烧后的炭层更加致密。     

四溴双酚A对HIPS共混材料阻燃及增韧性能影响的研究

采用四溴双酚A(TBBA)为阻燃剂对高抗冲聚苯乙烯(HIPS)共混材料进行阻燃改性;研究了TBBA的阻燃机理、TBBA含量、TBBA与三氧化二锑(Sb2O3)的协同效应及其对HIPS共混材料阻燃性能、力学性能和加工性能的影响。结果发现,当TBBA/Sb2O3的协同质量比为3∶1时,共混体系的阻燃效果最好;并比较了增韧剂种类和用量对HIPS共混材料阻燃性能、力学性能和加工性能的影响。     

氢氧化镁粒径对阻燃聚乙烯复合材料性能的影响

以三种粒径的氢氧化镁(1.5、3.1以及6.4μm)为阻燃剂,氢氧化镁与低密度聚乙烯共混,制备聚乙烯/氢氧化镁阻燃复合材料。研究氢氧化镁的粒径对复合材料力学性能、电学性能、阻燃性能以及热稳定性的影响。结果表明：当氢氧化镁粒径增至6.4μm,复合材料的拉伸强度与断裂伸长率分别降至14.2 MPa和199.0%。随着氢氧化镁粒径的增加,复合材料的阻燃性能逐渐提高。当氢氧化镁粒径增至6.4μm,复合材料的最大热释放速率降至350 kW/m²以下,氧指数(LOI)提高至22.8%。随着氢氧化镁粒径增加,复合材料的电学性能明显下降,介电损耗明显增加,体积电阻率由6.9×10¹³Ω·m降至1.5×10¹³Ω·m。综上分析,当氢氧化镁粒径为3.1μm,复合材料的综合性能最佳。     

挤出型无卤阻燃三元乙丙橡胶材料的制备与性能

研究了具有不同粒径、不同表面改性的氢氧化镁及其与磷系阻燃剂的并用物、石蜡油增塑剂等对EPDM力学性能、挤出加工性能和阻燃性能的影响.结果表明:纳米氢氧化镁兼具增强和阻燃特性,但大量添加时材料的硬度很高.通过大量微米氢氧化镁和少量纳米氢氧化镁并用,辅以少量磷系阻燃协效剂和成炭剂,协调阻燃性能和力学性能的要求.通过添加少量马来酸酐接枝三元乙丙橡胶、润滑剂并加入石蜡油,可明显改善EPDM的挤出加工性能,最终制备出一种综合性能较好的挤出型无卤阻燃EPDM材料.     

SA／CaSt改陛氯氧化镁／MCA阻燃抗熔滴PA6的性能研究

以硫酸镁与氨水为原料,采用硬脂酸／硬脂酸钙作为复合改性剂,合成改性氢氧化镁阻燃剂。将制备的改性氢氧化镁与三聚氰胺氰尿酸盐（MCA）添加到尼龙（PA6）中,通过挤出造粒制备复合阻燃（PA6）。分别研究不同阻燃剂配比对复合材料力学性能、耐热性能、阻燃性能及机理的影响。结果表明：随着MCA／改性氢氧化镁比例的增大,复合阻燃PA6的拉伸性能与冲击性能均先上升后下降,当两者比例为1：1时,力学性能达到最优。同时,两阻燃剂协同作用,使尼龙6阻燃机理由解聚分解转化为直接炭化分解,有效抑制燃烧流滴现象,提高了复合材料的综合阻燃性能。     

LLDPE/EPDM复合材料高效阻燃体系的研究

以线性低密度聚乙烯(LLDPE)、(乙烯／丙烯／二烯)共聚物(EPDM)为基体,以经表面处理的氢氧化镁[Mg(OH)2]为主阻燃剂,微胶囊化红磷和自制阻燃剂S为核心的复合阻燃剂为阻燃增效剂,制备了阻燃性能优良的LLDPE／EPDM复合材料。重点探讨了Mg(OH)2与复合阻燃剂的阻燃效果及其对LLDPE／EPDM复合材料力学性能、加工性能的影响。结果表明,Mg(OH)2与复合阻燃剂并用具有良好的协同效应,当MS(OH)2用量为40份、复合阻燃剂用量为5-7份时,可获得较高的氧指数和垂直燃烧FV-0级的高阻燃性,且材料的加工性能和力学性能较好。     

硫化体系对EPDM耐热老化性能的影响

研究了普通硫化体系 (CV)、半有效硫化体系 (SEV)和有效硫化体系 (EV)的硫化特性及其对EPDM力学性能和耐热老化性能的影响 ,以及防老剂对EPDM耐热老化性能的影响。试验结果表明 ,采用SEV和EV体系硫化的硫化胶有较好的耐热老化性能 ,采用CV体系的硫化胶有较好的力学性能 ;防老剂对EPDM的耐热老化性能无明显影响。     

丁羟型聚氨酯弹性体力学性能研究

研究了以不同分子质量的丁羟（HTPB）、二异氰酸酯和固化剂为主要原料制备的PU弹性体的力学性能。结果表明,PU弹性体的力学性能随丁羟相对分子质量的增大而提高;R（n-NCO／n-OH）值达到8时,PU的力学性能最佳;用4种固化剂固化PU弹性体,结果表明复配的固化剂固化的PU弹性体力学性能最好;固化温度越高、时间越长,PU弹性体的力学性能越好。     

Effect of processing conditions on the structure and properties of polypropylene spunbond fabrics

The structure and properties of a spunbond fabric are determined by numerous process variables. The development of fiber morphology is influenced and controlled by extrusion and quenching conditions. The properties of the fabric are the result of the properties of the filaments, their arrangement in the web, and the bonding conditions. It is therefore critical to understand the relationship between the process conditions and the properties of the fabrics produced. This study was conducted to investigate the effects of some of the important process variables on the structure and properties of the filaments and ultimately on that of the fabrics. Process variables such as polymer throughput rate, cooling and suction air speed, web basis weight, and bonding temperature were investigated. Filament samples were collected before bonding and were analyzed for various properties such as crystallinity, crystallite size, birefringence, density, thermomechanical stability, and tensile properties. The fabric samples were analyzed for tensile properties, tear strength, stiffness, and crystallinity. Ruptured strips obtained from the tensile test were observed with a scanning electron microscope to understand the failure mechanism. The results were statistically analyzed to evaluate the effect of process variables on the properties and to predict the properties for different process conditions. The findings are helpful in determining the optimum processing conditions so as to achieve the desired properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2355–2364, 2005     

Structural and tribological characterization of amorphous and crystalline titanium-nickel coatings

The interest in titanium-nickel (TiNi) alloys has increased with the discovery of the versatile properties of these alloys. In this study, the structural, mechanical and tribological properties of amorphous and crystalline TiNi coatings were investigated. The TiNi coatings were deposited with magnetron sputtering system. The crystallization process was conducted in a vacuum heat treatment furnace. The structural properties of the coatings were investigated with XRD, SEM and EDS analyses. Micro-hardness and pin-on-disc wear tests were used to obtain the mechanical and tribological properties of the coatings. AISI D2 steel, AISI 52100 steel, Aluminum 2024 alloy and copper were used as substrate materials, hence the effects of different substrates were also investigated. The highest coating hardness was obtained as 8.5?GPa and the lowest coefficient of friction value was obtained as 0.18. The tribological tests showed that the amorphous and crystalline TiNi coatings have different coefficient of friction and wear rate and using different substrate affects these properties.     

白炭黑补强异戊橡胶和天然橡胶性能的对比研究

采用白炭黑填充补强异戊橡胶(IR)和天然橡胶(NR),分别研究其硫化特性、机械力学性能、热空气老化性能和动态力学性能.结果表明:白炭黑补强的IR比NR硫化速度快,焦烧时间短,交联密度与NR接近;NR的机械力学性能优于IR;随着白炭黑用量增加,IR的耐老化能力逐渐增强,NR在白炭黑用量为20份时耐老化性能最好;在0℃时,IR的损耗因子大于NR的损耗因子,在60℃时,IR的损耗因子小于NR的损耗因子.     

不同无卤阻燃剂对PPO/HIPS合金性能影响研究

制备了不同质量比的聚苯醚/高抗冲聚苯乙烯(PPO/HIPS)合金材料,PPO/HIPS质量比为60∶40时合金的综合性能最佳。研究了不同无卤阻燃剂三苯基氧化膦(PX220)、PX220/三聚氰胺聚磷酸盐(MPP)及红磷阻燃剂(RPM650)对PPO/HIPS合金材料阻燃性能、力学性能及热性能的影响。结果表明:在添加相同质量阻燃剂的情况下,PX220/MPP复配阻燃剂可使PPO/HIPS合金材料具有较高的负荷变形温度和熔体质量流动速率,以及优异的阻燃性能和力学性能;无卤阻燃剂的加入使PPO/HIPS合金的初始分解温度降低,最大热失重速率峰值向低温区移动。     

Effect of the Activator Type and Catalyst/Activator Ratio on Physical and Mechanical Properties of Cast PA-6

The aim of the study is to produce suitable unfilled cast polyamide-6 composition exhibiting optimum mechanical, physical, thermal and electrical properties with anionic polymerization mechanism. Sodium lactamate was used as catalyst at all compositions. Activators used were varied as toluenediisocyanate (TDI), isophronediisocyanate (IPDI), hexamethylenediisocyanate (HMDI) and diphenylmethylenediamine (DPMD). Also, activator and catalyst content were varied between 0.4–0.8% and 1–4% respectively. The best mechanical properties were attained with using TDI as activator at 0.488%. Then, other properties of this composition were determined. Comparison of these properties with other plastics showed that it had the highest abrasion resistance, lower water absorption, higher tensile and flexural strength.     

硼酸锌插层氢氧化镁阻燃EVA的研制

以氢氧化镁为躯体,氧化锌和硼酸为插层剂制得插层氢氧化镁阻燃复合材料,用激光粒度分析仪及高扫描显微镜（SEM）表征插层氢氧化镁的表面性质;将该阻燃剂添加到乙烯-醋酸乙烯酯共聚物（EVA）中,加入适量EVA—D4085相容剂。考查了复合材料阻燃性能、力学性能、热力学性能以及吸潮性。     

Estimation of Thermodynamic Properties of Polysaccharides

Polysaccharides are the most important components of herbal biomass with a high application potential. Their thermochemical characteristics, however, have been little studied. In the present paper, an effective thermodynamic analysis was carried out with the aim of setting a method for reasonably estimating the thermochemical properties of polysaccharides such as cellulose. The properties of formation and heat capacities were estimated by general thermodynamic methods like group contribution methods as well as methods followed from synthetic polymer studies. The results were compared with those obtained by empirical correlations derived from the data for short chain carbohydrates, the only literature data available for validation. The properties were determined depending on the degree of polymerization and temperature.     

Effect of molecular weight of phenalkamines on the curing,mechanical, thermal and anticorrosive properties of epoxy based coatings

The present investigation deals with the study of effect of molecular weight and structures of phenalkamine curing agents on the curing, mechanical, thermal and anticorrosive properties of epoxy based coatings. The phenalkamines were prepared by varying the composition of formaldehyde and diamine in the formulation. The structural characterization confirmed successful preparation of high molecular weight phenalkamines. These were then used as curing agents for air drying and thermally curable epoxy coatings. The effect of these phenalkamines on curing properties of epoxy resin as well as mechanical, chemical, thermal and dynamic thermo-mechanical properties of the resultant coatings was studied and compared with commercial phenalkamine. The anticorrosive properties of the coatings were evaluated by salt spray test and electrochemical impedance spectroscopy. The study revealed that high molecular weight phenalkamines resulted in faster surface drying due to rapid molecular weight build-up. The anticorrosive performance also improved as indicated by higher modulus and electrochemical potential values.