四种聚乙烯醇的特性粘度（浓度与比浓粘度）研究

通过对聚乙烯醇17-99H、100．37H、100-50H及100-60L的特性粘度（浓度与比浓粘度）进行研究,发现比浓粘度与浓度不成直线关系,出现了“w”折线图,即得不到聚乙烯醇的特性粘度。图中的“峰”“谷”与聚乙烯醇的组成关系,有待下一步分离、纯化后实验研究求证。     

Liquid Natural Rubber as a Viscosity Modifier in Nitrile Rubber Processing

The use of thermally depolymerised liquid natural rubber as a plasticiser in nitrile rubber has been investigated with special reference to the rheological aspects. A comparative evaluation has been made with dibutylphthalate, the ester-type plasticiser commonly used with nitrile rubber. The study revealed that the use of liquid natural rubber as a plasticiser and viscosity modifier improved the processability of the compounds and also enhanced many of the vulcanisate properties. © of SCI.     

Biocomposites of Epoxidized Natural Rubber/Poly(lactic acid) Modified with Natural Fillers (Part I)

The study aimed to prepare sustainable and degradable elastic blends of epoxidized natural rubber (ENR) with poly(lactic acid) (PLA) that were reinforced with flax fiber (FF) and montmorillonite (MMT), simultaneously filling the gap in the literature regarding the PLA-containing polymer blends filled with natural additives. The performed study reveals that FF incorporation into ENR/PLA blend may cause a significant improvement in tensile strength from (10 ± 1) MPa for the reference material to (19 ± 2) MPa for the fibers-filled blend. Additionally, it was found that MMT employment in the role of the filler might contribute to ENR/PLA plasticization and considerably promote the blend elongation up to 600%. This proves the successful creation of the unique and eco-friendly PLA-containing polymer blend exhibiting high elasticity. Moreover, thanks to the performed accelerated thermo-oxidative and ultraviolet (UV) aging, it was established that MMT incorporation may delay the degradation of ENR/PLA blends under the abovementioned conditions. Additionally, mold tests revealed that plant-derived fiber addition might highly enhance the ENR/PLA blend’s biodeterioration potential enabling faster and more efficient growth of microorganisms. Therefore, materials presented in this research may become competitive and eco-friendly alternatives to commonly utilized petro-based polymeric products.     

降解天然橡胶胶乳的接枝共聚研究

研究了不同降解程度的天然橡胶胶乳与丙烯酸丁酯 ( BA)的接枝反应及反应条件对接枝率的影响。发现随着降解时间增加 ,降解橡胶的粘均相对分子质量降低不是直线下降 ,而是有一个明显的突跃 ,降解胶乳共聚反应活性并未降低 ,且共聚物中 BA聚合链段与橡胶链段的相对比例 (质量比 )明显增加     

羰基试剂对天然橡胶恒粘效果的研究

研究了几种羰基试剂处理天然胶的恒粘效果及其对恒粘胶理化性能的影响,可以获得低粘度、中粘度、和高粘度的恒粘天然橡胶。结果表明,鲜胶乳用羰基试剂处理后,其生胶加速贮存后的门尼粘度变化量为0～3个门尼值,加速贮存硬化值变化量为0～1个单位塑性值,恒粘效果较好,其它的理化性能虽有所变化,但均能达到国家标准要求。     

低代数聚丙烯亚胺树形分子的合成与表征

对聚丙烯亚胺树形分子的合成进行了研究。通过优化反应条件 ,如提高反应温度、增大反应物浓度、加入少量醋酸作为催化剂、选择氨 甲醇作为还原溶剂 ,提出了一条合成结构较为精确 ,可以最大程度减少或避免副反应的聚丙烯亚胺树形分子的合成路线。红外光谱表明优化条件下所得 0 5代聚丙烯亚胺树形分子反应完全 ,有利于结构增长 ;滴定法表明在氨 甲醇溶剂下还原所得 1 0代聚丙烯亚胺树形分子中伯胺基的摩尔分数为x (NH2 ) =85 % ,比在甲醇条件下所得结果 [x(NH2 ) =76 % ]有较大提高。1H核磁共振、元素分析也表明所合成的低代数聚丙烯亚胺树形分子结构精确 ,达到了分子设计的目的。     

橡胶加工分析仪研究环氧化天然橡胶的性能

用橡胶加工分析仪对环氧化天然橡胶进行了温度扫描、频率扫描和应变扫描，并和天然橡胶的响应曲线进行了对比。     

腈纶聚合物特性粘度测定关键因素的控制

腈纶生产中,丙烯腈高分子聚合物特性粘度的正确测定致关重要,它直接关系到后续工序是否能稳定运行,以及最终产品腈纶纤维的各项物化指标.介绍了腈纶生产中丙烯腈高分子聚合物特性粘度的测定原理、测定方法以及极为重要的关键因素的控制.     

复合成核剂对PET结晶速率和特性黏数的影响

采用差示扫描量热分析仪和乌氏黏度计研究了不同成核剂及其复配对聚对苯二甲酸乙二醇酯（PET）结晶速率和特性黏数的影响。结果表明,复合成核剂对于提高PET成核结晶速率[半结晶时间（t1/2）为32.3~45.3 s]的效果优于单一成核剂（t1/2为42.9~57.9 s）;同时部分复合成核剂能有效减小PET特性黏数的降低幅度。     

聚（癸二酸-1,3-丙二醇）酯低聚物的合成与表征

在无催化剂、相对较低温度下合成了聚(癸二酸-1,3-丙二醇)酯低聚物。GPC色谱显示,过量1,3-丙二醇常使粗产物呈现多组分,但随其用量减少,粗产物逐渐变均一。FTIR光谱表明,低聚物主链为酯键结构,且羟基含量随单体摩尔比降低及第二阶段反应进行而趋于减小。1H NMR分析发现,低聚物实际摩尔组成远低于初始单体摩尔比;低聚物摩尔质量为967.14～3970.49g/mol,1,3-丙二醇封端度为38%～66%。该低聚物期望在口香糖制备中用作无毒、环境友好、可生物降解型增塑剂。     

活化胶粉在橡胶中的应用

研究活化胶粉的主要性能及在胎面和制品中的应用。实验结果表明,充填４０目活化胶粉之硫化胶性能明显优于充填等量未活化胶粉者。随着活化胶粉用量从Ｏｐｈｒ增至３０ｐｈｒ,ＮＲ／ＢＲ／活化胶粉共混胶的ＭＬ值和挤出应力增大,挤出物外观稍变差,但出口膨胀值降低,挤出物尺寸稳定性好;焦烧和正硫化时间缩短,硫化速度加快;ＮＲ／ＢＲ／活化胶粉共混硫化胶的３００％定伸应力、硬度、撕裂强度、回弹性、热老化性均较无活化胶粉者有不同程度提高,但拉伸强度、扯断伸长率、永久变形、耐磨性、湿滑指数及疲劳性等均有所降低。实际使用证明,在胎面胶添加１０～２５ｐｈｒ４０目活化胶粉及在橡胶制品中加入适量２８目活化胶粉是可行的     

Interfacial Polymerization of Linear Aromatic Poly(ester amide)s

Linear aromatic poly(ester amide)s (PEAs) have been synthesized by interfacial polycondensation (IPC) of aromatic diamidoacid chloride: 2-{[4-({[2-(chlorocarbonyl) phenyl]amino} carbonyl) benzoyl]amino} benzoyl chloride (2CCBC), with ethylene glycol, bisphenol A, resorcinol, 4,4′-bis(4-hydroxybenzilidine)diaminobenzanilide and 4,4′-bis(4-hydroxy benzilidine)-m-phenylenediamine in chloroform/water system employing phase-transfer-catalyst. The aromatic diamidoacid chloride has been prepared by condensation of terephthaloyl chloride with anthranilic acid. These polymers were characterized by elemental analysis, FTIR, ¹H-NMR, solubility studies, intrinsic viscosity and TGA analysis. The polyester-amides so obtained show good thermal stability.     

Comparison Properties of Natural Rubber (SMR L)/Ethylene Vinyl Acetate (EVA) Copolymer Blends and Epoxidized Natural Rubber (ENR-50)/Ethylene Vinyl Acetate (EVA) Copolymer Blends

Mixing torque, morphology, tensile properties and swelling studies of natural rubber/ethylene vinyl acetate copolymer blends were studied. Two series of unvulcanized blends, natural rubber/ethylene vinyl acetate (SMRL/EVA) copolymer blend and epoxidized natural rubber (50% epoxidation)/ethylene vinyl acetate (ENR-50/EVA) copolymer blend were prepared. Blends were prepared using a laboratory internal mixer, Haake Rheomix polydrive with rotor speed of 50 rpm at 120°C. Results indicated that mixing torque value and stabilization torque value in ENR-50 blends are lower than SMRL blends. The process efficiency of ENR-50/EVA blends is better due to less viscous nature of the blend compared to SMRL/EVA blends as indicated in stabilization torque graph. Tensile properties like tensile strength, M100 (modulus at 100% elongation) and E _b (elongation at break) increase with increasing EVA fraction in the blend. At the similar blend composition, ENR-50 blend shows better tensile properties than SMRL blends. In oil resistance test, swelling percentage increased with immersion time and rubber composition. At a similar immersion time, ENR-50 blends exhibit better oil resistance compared to SMRL blends. Scanning electron microscopy (SEM) of tensile fractured surface indicated that EVA/ENR-50 blends need higher energy to cause catastrophic failure compared to EVA/SMRL blends. In etched cryogenically fractured surface, size and distribution of holes due to extraction of rubber phase by methyl ethyl ketone (MEK) were studied and holes became bigger as rubber composition increased due to coalescence of rubber particle.     

Synthesis and Characterization of Colored Poly(Urethane-Urea)

ABSTRACT

Various Poly(urethane-urea)s (PUU)s were prepared by polycondensation of various azo dyes having both amino and hydroxyl group with Toluene 2,4-diisocyanate. The resultant poly(urethane-urea)s were characterized by the elementary analysis, IR spectral, nonaqueous conductometric titration, and thermogravimetry. The electrical conductivity of these oligomers has also been measured at room temperature.     

Impact,Thermal, and Morphological Properties of Poly(Lactic Acid)/Poly(Methyl Methacrylate)/Halloysite Nanotube Nanocomposites

Poly(lactic acid)/poly(methyl methacrylate) blends containing halloysite nanotube (2 and 5 phr) and epoxidized natural rubber (5–15 phr) were prepared by melt mixing. The impact strength of poly(lactic acid)/poly(methyl methacrylate) blend was slightly improved by the addition of halloysite nanotube. Adding epoxidized natural rubber further increased the impact strength of poly(lactic acid)/poly(methyl methacrylate)/halloysite nanotube nanocomposite. Single T_g of poly(lactic acid)/poly(methyl methacrylate) is observed and this indicates that poly(lactic acid)/poly(methyl methacrylate) blend is miscible. The addition of halloysite nanotube into poly(lactic acid)/poly(methyl methacrylate) slightly increased the T_g of the blends. The epoxidized natural rubber could encapsulate some of the halloysite nanotube and prevent the halloysite nanotube from breaking into shorter length tube during the melt shearing process.     

不同熔融混炼条件下PET的降解行为和结晶行为

采用不同预处理条件对聚对苯二甲酸乙二醇酯（PET）切片进行熔融混炼,考察了不同熔融混炼条件下PET的降解行为和结晶行为。结果表明,不同条件的熔融混炼过程均导致PET降解,而降解速率和样品含水率密切相关;PET的降解不仅导致其结晶速率提高,也将导致其球晶晶片厚度增加和结晶度增大;PET的结晶峰值温度（Tcp）、结晶起始温度（Tonset）和结晶结束温度（Tendset）与其特性黏度\[η\]之间存在相关关系,表现为\[η\]越小,Tcp越高,结晶速率越快。     

聚(2,5-二甲基对苯乙炔)前聚物的合成及表征

以对二甲苯为原料,经三步化学反应合成聚（２,５－二甲基－１,４－亚苯基－１′,２′－乙二撑－１′－氯化二乙锍盐）,讨论了温度、气氛和溶剂对聚合反应的影响。产品的结构由ＩＲ和１ＨＮＭＲ光谱得到确认     

Rayleigh散射研究非相容聚苯乙烯／顺丁橡胶合金相结构

用光散射在线采集与分析方法完成了熔融混炼过程中非相容高分子共混物的形态结构分析。选择了聚苯乙烯／顺丁橡胶合金体系。使用了小角前向光散射和小角背散射（在线）技术，用Debye-Bueche光散射理论的结构参数如相关蹁ac、平均弦长l、平均旋转半径Rg和积分不变量Q表征了共混物中分散相尺度和均匀性。用扫描电子显微镜（SEM）测定了共混物中分散相尺寸，并与光散射的结果进行了比较。ac,l和Rg的变化规律与显微镜的结果是一致的。用积分不变量Q研究了共混物的均匀性。     

Effects of Dynamic Vulcanization and Acrylic Acid on Properties of Recycled Poly(vinyl chloride)/Acrylonitrile Butadiene Rubber (PVCr/NBR) Blends

Effects of dynamic vulcanization and acrylic acid (AAc) on processability, mechanical properties, swelling behavior, morphology, and thermal stability of recycled poly(vinyl chloride)/acrylonitrile butadiene rubber (PVCr/NBR) blends were investigated. Blends were prepared in a Haake Rheomix at a temperature of 150°C and a rotor speed of 50 rpm. Recycled poly(vinyl chloride)/acrylonitrile butadiene rubber (PVCr/NBR) blends were also prepared as comparison. It was found that the dynamic vulcanization and the addition of acrylic acid improved the stabilization torque, mechanical energy, stress at peak, stress at 100% elongation (M₁₀₀), swelling resistance, and thermal stability but decreased the elongation at break of the blends. The introduction of a cross-link into the elastomer phase and better compatibility between PVCr and NBR are responsible for the enhancement of thermal stability and mechanical properties of dynamically vulcanized PVCr/NBR + AAc as evidence from the scanning electron microscopy (SEM) of the tensile fracture surfaces and infrared spectroscopy study of the dynamically vulcanized of PVCr/NBR + AAc shows.     

Rheology and Processability of Natural Rubber Composites with Mica

This work is concerned with the influence of mica in natural rubber compounds on properties such as Mooney viscosity, processability and rheological behavior. The amount of this filler was varied from 0 to 40 phr and the stabilized and totalized torques, specific and mechanical energies were determined in a HAAKE torque rheometer. The elastic torque (S′) and complex dynamic viscosity (η?) were measured on a rubber processing analyzer (RPA). The results show that mica influences processability and rheological properties, by acting as a processing agent in natural rubber composites.