用双螺杆挤出机脱硫制备再生胶的工艺及性能

利用改进的双螺杆挤出机对废旧轮胎橡胶胶粉进行剪切脱硫,讨论了螺杆转速和反应温度对脱硫效果及再生胶力学性能的影响,通过扫描电镜分析了胶粉脱硫前后形貌的变化及再生胶硫化试样的界面结合状况。结果表明,废旧轮胎橡胶胶粉的凝胶含量和交联密度随着螺杆转速和反应温度的升高明显下降,脱硫胶粉恢复了塑性,再生胶硫化试样的界面结合紧密。将螺杆转速控制在50～120 r/min、反应温度控制在190/180/170～210/190/200℃时脱硫效果最佳,此时再生胶的拉伸强度由未脱硫前的3.1 MPa提高到了12.4 MPa,扯断伸长率由75%提高到452%。     

Aromatic-aliphatic copolyesters: structure and properties

Aromatic-aliphatic copolyesters synthesized by interfacial polycondensation were characterized by differential scanning calorimetry. X-ray diffraction and density measurements. A decrease in the T_g and melting temperature was observed on increasing the glycol content of the copolyesters. The wholly aromatic polyesters showed changes both in the Bragg angle position and intensity of the reflections, whereas in the aromatic-aliphatic copolyesters no sharp change was observed.     

用同向双螺杆挤出机制备液体脱硫橡胶

采用双螺杆挤出机将废胶粉进行连续脱硫以制备溶胶含量较高的脱硫橡胶,脱硫橡胶可呈流体状态。影响脱硫效果的工艺因素主要有螺杆转速、机筒温度、废胶粉的粒径以及添加剂的用量。对脱硫橡胶进行了溶胶含量、门尼黏度、凝胶渗透色谱及差示扫描量热等的测试分析,结果表明,提高螺杆转速会降低橡胶的溶胶含量,升高机筒温度可以有效提高橡胶的溶胶含量,胶粉粒径越大制得的脱硫橡胶的溶胶含量越低,增加脱硫剂的用量可以提高橡胶的溶胶含量。通过温度、螺杆转速和添加剂用量的选择可以得到脱硫程度不同的脱硫橡胶。     

低结合苯乙烯含量溶聚丁苯橡胶的制备及性能

以四氢糠醚(THFA)为结构调节剂合成了结合苯乙烯质量分数为15％的溶聚丁苯橡胶(SSBR),考察了结构调节剂THFA的用量、聚合温度对微观结构、耐低温性能、门尼黏度及拉伸强度的影响.结果表明,玻璃化转变温度(Tg)随结合苯乙烯质量分数的增加呈线性增加;随THFA用量的增加,1,2-结构质量分数增大,Tg随着THFA用...     

Melt flow and fiber properties of copolyesters

The effect of modifying monomer [sodium 3,5-di(carbonethoxy)benzene sulfonate] contents range from 1.5 to 4.5 mol % on the melt flow and fiber properties of copolyesters (COPET) dyeable with basic dyes was investigated. An Instron capillary rheometer was used to obtain data over shear rates ranging from 10 to 10⁴ s^?1 at 265, 275, and 285°C. The COPET's flow properties as a function of temperature, inherent viscosity, melting point, and modifying monomer content were determined. The drawn fibers annealed in oil and air at 80, 110, 130, 150, 175, and 200°C were studied by means of measurements of shrinkage ratio, crystallinity, birefringence, long period, sonic rate, and static state flexibility of molecular chain. All these showed that the large side group, ? SO₃Na in COPET molecular chains causes an increase in chain rigidity and melt viscosity, and a decrease in crystallinity and orientation.     

可生物降解脂肪-芳香族共聚酯的结构与性能

采用稀土催化剂,以1,4-丁二醇、己二酸和对苯二甲酸二甲酯为原料制备了聚己二酸丁二酯和对苯二甲酸丁二酯的系列共聚酯,测试了共聚酯的相对分子质量、力学性能、热性能、组成和微观结构。采用堆肥埋片法,考察了共聚酯的生物降解性。随着共聚酯中所含芳香组分的增多,其力学性能增强,热性能提高,熔点先由57℃降到32℃后,再逐渐升至145℃。共聚酯的生物降解性则随芳香组分增多而变差。     

Rheological properties of liquid crystalline copolyesters

Copolyesters were synthesized by modifying poly(ethylene terephthalate) (PET) with p-acetoxybenzoic acid (PAB) and hydroquinone diacetate/tetrasubstituted (tetramethyl, tetrachloro, and tetabromo) terephthalic acid (HQTS). It was found that the copolyesters containing 33 mol% or higher concentrations of (PAB+HQTS) from mesomorphic liquid crystalline structures. Rheological properties of copolyesters formed of PET, modified with PAB and hydroquinone diacetate/tetramethyl terephthalic acid (HQTM), were measured using a cone-and-plate rheometer. It was found that the copolyesters in the mesomorphic state exhibit yield values at a low shear rate (or at a low shear stress), and negative values of first normal stress difference were observed for certain compositions of (PAB+HQTM), over the range of shear rates (or shear stresses) tested.     

Structure and properties of liquid crystalline naphthalenediol copolyesters

Thermotropic liquid crystalline copolyesters with 1.4-, 1.5-, and 2.7-naphthalenediol (NDO) units were prepared by molten-state copolycondensation. It was found that the chain structure of the copolyesters is almost the same as the structure of recurring moieties of five units. The copolyesters have a glass transition temperature above 381 K, decomposition temperature above 703 K, and melting temperature between 513 and 559 K and their melts exhibit nematic texture and stir opalescence. The copolyester melts show a usual rheological behavior depending on the NDO unit content, but much lower extrudate swell. Light-scattering patterns of the copolyester films with low crystallinity are clearly asymmetric and therefore indicate the existence of preferred orientation of the copolyester chains. Scanning electron microscopy observation suggests that the as-spun fibers of 2.7-NDO-containing copolyesters were highly oriented and fibrillated. © 1994 John Wiley & Sons, Inc.     

聚硅酸锌镁的制备及其性能

以硅酸钠、硫酸锌、硫酸镁为原料,通过共聚法制备了无机高分子絮凝剂聚硅酸锌镁（PSMZS）,研究了Na2SiO3的摩尔浓度、活化时间、Mg/Si、Zn/Si 配比及絮凝剂的投加量对絮凝效果的影响,用X射线衍射（XRD）和电子扫描电镜（SEM）对该絮凝剂的结构及形貌进行了表征。结果表明：当Na2SiO3的浓度为0.4 mol/L,硅酸活化时间为1.5 h,Si/Mg的摩尔比为1∶5,Zn/Si摩尔比为0.5,絮凝剂投加量为25 mL/L废水时,絮凝剂的电中和能力和吸附架桥能力最强,絮凝剂对含H-酸染料模拟废水的絮凝效果最好。     

共聚酯的结晶性能研究

通过添加二元酸或二元醇来制备共聚酯,采用DSC对共聚酯的结晶性能展开研究,分析了二元酸或二元醇对共聚酯结晶性能的影响。     

可聚合阳离子含氟表面活性剂的合成与性能研究

本文以全氟烷基乙基醇（PFEA）为原料,设计合成了三种不同含氟链段长度的可聚合阳离子含氟表面活性剂—N-（乙酸全氟烷基乙基酯）-N-（乙醇丙烯酸酯）二甲基溴化铵（PFDM）,通过核磁共振氢谱（1H NMR）对其结构进行了表征。利用Zeta电位测定、表面张力测定等手段考察了不同含氟链段长度对PFDM表面活性等的影响,并证明了PFDM的可聚合性。结果表明,随含氟链段的增长PFDM在水介质中形成胶束的胶束聚集数逐渐增大,CMC呈指数下降,表面活性逐渐增强,且具有良好的可聚合性。     

低熔点PBT共聚酯的制备及其熔融结晶行为分析

以间苯二甲酸(IPA)作为第三单体,采用直接酯化熔融缩聚的方法制备了低熔点聚对苯二甲酸丁二醇酯(PBT)共聚酯(PIBT)。采用乌氏黏度计、差示扫描量热仪和偏光显微镜分别对PIBT的黏均相对分子质量(Mη)、熔融和结晶行为进行了表征和研究。结果表明:制备的PIBT的Mη均达到聚合物水平;随着IPA含量的增加,PIBT的熔点逐渐降低,当IPA摩尔分数为15%时,PIBT的熔点为201.68℃,与PBT的熔点相比下降了24.21℃;在相同降温速率下,随着IPA含量的增加,PIBT的结晶温度及结晶速率常数逐渐降低,结晶速率逐渐变慢,PIBT等温结晶所得球晶直径逐渐变小。     

由精制松香催化聚合制备二聚松香的研究

以SO24-/ZrO2、SO24-/TiO2、SO24-/ZnCl2为催化剂,采用精制松香为原料催化聚合制备二聚松香,利用色谱法分析二聚松香的含量.结果表明:最宜采用SO24-/ZnCl2作催化剂,其中n(H2SO4)∶n(ZnCl2)=0.6.在松香与溶剂质量比为1:1、SO24-/ZnCl2的用量为10%(m/m)、搅拌强度为800 rpm、120℃保温聚合反应10 h和270℃减压蒸馏(200 Pa)的条件下,制备了符合ZBB 72088-89规定的一级二聚松香:含量92%,软化点182℃,酸值150.6 mg KOH/g,收率≥74%;二级二聚松香:含量≥65.5%,软化点135℃,酸值157 mg KOH/g,收率≥95%.     

Rheological properties of thermotropic liquid crystalline aromatic copolyesters

A series of thermotropic liquid crystalline polyesters based on p-acetoxybenzoic acid, naphthalene dicarboxylic acid, hydroquinone diacetate, and poly(ethylene terephthalate) were prepared via melt polycondensation. The anisotropic melts were studied by means of thermal optical testing, differential scanning calorimetry, scanning electron microscopy. X-ray diffraction, and rheological methods. It was found that the copolyesters in the mesomorphic state exhibit drastic shear-thinning and the experimental results indicate that the non-Newtonian Index n is in the range of 0.17 to 0.50, the flow-activation energies ΔE_η are 297.1 to 182.0 KJ/mol over the shear rate of 10 to 1000 S^?1 at temperature 225 to 270°C; and the mesomorphic copolymers are readily oriented during processing, resulting in highly oriented as-spun fibers.     

Structure and mechanical properties of blends of two thermotropic copolyesters

Blends of two thermotropic copolyesters, poly(ethylene terephthalate/p‐hydroxy benzoic acid) (20/80), EB, and poly(p‐hydroxy benzoic acid/2,6‐hydroxy naphthoic acid) (73/27), BN, were obtained in the melt state by direct mixing in an injection machine throughout the full composition range. They comprised an almost pure EB phase and a BN‐rich phase that contained some reacted EB. Important synergisms with most of the values above those of the two pure blend components were found at most compositions in the modulus of elasticity and the tensile strength. The synergisms appeared to be due to the concomitant effect mainly of an orientation of the components higher in the blends than in the pure components, and to a lesser extent, of a blending‐induced specific volume decrease.     

Synthesis and properties of aromatic copolyesters with different monomer sequences

Summary A random aromatic copolyester was prepared from 111 molar ratio of p-hydroxybenzoic acid, hydroquinone and isophthalic acid. The properties of the polymer were compared with those of the polyner prepared from 4-hydroxyphenyl-4-hydroxybenzoate and isophthalic acid. These two copolyesters have different monomer sequences, but the same overall compositions. It was found that the latter exhibits much higher melting point and also higher degree of crystallinity than the former. Moreover, their crystal structures seem to be quite different. Both of them are themotropic.     

Preparation and properties of in‐situ polymerized polyurethane/stearate intercalated layer double hydroxide nanocomposites

The present work deals with the effect of stearate intercalated layered double hydroxide (St‐LDH) loadings on the morphological, mechanical, thermal, adhesive and flame retardant properties of polyurethane (PU)/St‐LDH nanocomposites prepared by the in situ polymerization method. X‐ray diffraction and transmission electron microscopy studies confirmed that exfoliation takes place at 3 wt% loading followed by intercalation at higher filler loadings in the PU matrix. The exfoliated structure has been further verified by atomic force microscopy. The measurements of stress‐strain, thermogravimetric analysis, dynamic mechanical analysis, lap shear strength and peel strength analysis showed that the nanocomposites containing 3 wt% St‐LDH exhibit excellent improvement in tensile strength (ca 175%) and log storage modulus (ca 14%), while PU/St‐LDH (5 wt%) possesses optimum improvement in glass transition temperature (ca 6 °C), lap shear strength (200%) and peel strength (130%) over neat PU. In addition, the gradual improvements in limiting oxygen index value with St‐LDH loading indicated the higher effectiveness in providing better barrier properties as well as better flame retardant behavior. Copyright © 2012 Society of Chemical Industry     

Preparation and properties of organic-inorganic hybrids based on poly(methyl methacrylate) and sol-gel polymerized 3-glycidyloxypropyltrimethoxysilane

New organic-inorganic hybrid materials were prepared by the sol-gel process. Simultaneous polymerizations of methyl methacrylate (MMA) and an organically modified silicon alkoxide, 3-glycidyloxypropyltrimethoxysilane (GLYMO), with varying MMA/GLYMO molar ratios, were performed. Poly(oxypropylene)diamine was used as an epoxy opening agent, as basic catalyst for GLYMO condensation and as poly(methyl methacrylate) (PMMA) crosslinking agent. Chemical reactions and the structure of prepared hybrids were studied by means of Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and by scanning electron microscopy (SEM). Depending on the ratios of organic and inorganic components hybrids showed either a discrete microstructure or interpenetrating polymer network (IPN) structure. Silsesquioxane (SSQO) structures formed as a result of GLYMO hydrolysis and condensation in the sol-gel process influence the glass-transition temperature of PMMA. The hybrids have much better thermal stability than PMMA, their surfaces are more hydrophilic than PMMA and they may have potential as damping materials.     

炭黑-SiO2双相纳米填料的制备、结构及其填充溶聚丁苯橡胶的性能

分析了炭黑-SiO2双相纳米填料(CSDF)的制备工艺条件、相态结构及其组成,并研究了CSDF填充溶聚丁苯橡胶(SSBR)体系的相态结构及性能。结果表明,采用凝胶-相容复合法,控制硅凝胶溶液的pH值为7,加入表面活性剂十六烷基三甲基溴化铵和炭黑,经24h陈化后可制备纳米掺杂的CSDF1;CSDF1在填充SSBR体系中分散均匀,体系的拉伸强度、扯断伸长率及撕裂强度明显高于炭黑填充SSBR体系,滞后损失低于炭黑填充SSBR体系,且CSDF1填充SSBR体系的性能也优于凝胶-复合法和物理掺混法分别制备的CSDF2、CSDF3填充SSBR体系。