NR/BR并用胶的共混方法与微观结构和强度之间的相互关系(上)

该研究用实验来说明并用胶中相形态扣填料分布影响的相互关系,并确定使用相容剂或者特别的共混技术是否对天然橡胶,顺丁橡胶（NR/BR）并用胶的性能有有利的影响。NR／BR并用胶既用母炼胶法也用单段共混法制备,采用了能给予两弹性体相之间有同等交联分布的硫化体系;测量了并用胶的形态、拉伸强度扣撕裂强度。实验结果表明,即使用粘度很不同的母炼胶,也能快速方便地生产具有高度相容性和精细结构的并用胶。通过将简单的混合规则应用到在相同条件下混炼的单个胶料中,这些精细结构的母炼胶法并用胶的强度性能可被预测。虽然粗糙形态在特别情况下可能产生高抗撕裂,但是对于多数应用场合,精细结构能给予较为满意的拉伸强度和撕裂强度性能。对于单段共混法的并用胶,对精细结构形态研究的发展比对填料分散的研究快得多。对于含有最佳硫化体系的NR／BR并用胶,结论是：应当选择能使填充剂最佳分散的共混周期,而应用相容剂并不能显著地缩短共混周期或改善并用胶的性能。     

NR/BR并用胶的共混方法与微观结构和强度之间的相互关系(下)

该研究用实验来说明并用胶中相形态和填料分布影响的相互关系,并确定使用相容荆或者特别的共混技术是否对天然橡胶,顺丁橡胶（NR／BR）并用胶的性能有有利的影响。NR／BR并用胶既用母炼胶法也用单段共混法制备,采用了能给予两弹性体相之间有同等交联分布的硫化体系;测量了并用胶的形态、拉伸强度和撕裂强度。实验结果表明,即使用粘度很不同的母炼胶,也能快速方便地生产具有高度相容性和精细结构的并用胶。通过将简单的混合规则应用到在相同条件下混炼的单个胶料中。这些精细结构的母炼胶法并用胶的强度性能可被预测。虽然粗糙形态在特别情况下可能产生高抗撕裂,但是对于多数应用场合,精细结构能给予较为满意的拉伸强度和撕裂强度性能。对于单段共混法的并用胶,对精细结构形态研究的发展比对填料分散的研究快得多。对于含有最佳硫化体系的NR／BR并用胶,结论是：应当选择能使填充剂最佳分散的共混周期,而应用相容荆并不能显著地缩短共混周期或改善并用胶的性能。     

氯化聚乙烯与丁腈胶并用的研究

本文讨论了氯化聚乙烯与丁腈胶的相容性,以及不同硫化体系、各种炭黑填充体系和某些配合因素对共混胶物理机械性能、硫化历程和热氧化稳定性的影响。     

丁腈橡胶增容丁苯橡胶/聚氯乙烯共混体系

采用一系列结合丙烯腈质量分数不同的丁腈橡胶(NBR)作为丁苯橡胶(SBR)／聚氯乙烯(PVC)不相容共混物的增容剂,研究了SBR／PVC／NBR硫化胶的力学性能,并用扫描电子显微镜、傅里叶变换红外光谱仪和动态黏弹仪研究了该硫化胶的形态结构与相容性。结果表明,结合丙烯腈质量分数为20％～26％的NBR是SBR／PVC的优良增容剂,可提高共混物的力学性能,使SBR相和PVC相达到微细均匀化分散,并在两相之间形成了界面层,使得增容效果达到最佳。     

橡胶并用体系的新型助剂——均化剂

橡胶的并用是橡胶改性的重要途径,不同胶种的适当掺合可显著改善橡胶的加工性能和物理机械性能。但对于大多数橡胶来说,由于聚合物结构(对称性、立构性和极性)、结晶性、反应性、溶解度参数等不尽相同,相互间往往缺乏相容性,并用后的混炼胶微观上是不均匀的两相分散体系,而且分散稳     

尼龙11共混物形态结构对力学性能影响的研究

用扫描电子显微镜(SEM)对尼龙11共混物的形态结构造行了研究，探讨了形态结构对力学性能的影响。形态结构分析表明，接技物的加入，降低了界面间的表面张力，使两相分散均匀，分散度提高，增强了相间的粘接力，改善了尼龙11与聚乙烯的相容性。在保持拉伸强度基本不变的情况下，有效地提高了其冲击强度。     

NR、NBR与橡胶型CPE135B并用的研究

分析了天然橡胶（NR）、丁腈橡胶（NBR）与橡胶型CPE135B共混物的形态结构，并对其物理机械性能进行了研究。结果表明：NBR与CPE135B并用，分散相粒径较小，两相分散均匀，相容性那于NR与CPE135B并用；NR／CPE135B并用胶具有较高硬度，撕裂强度以及良好的耐老化性能，综合性能较好的并用胶其并用比为m(NR):m(CPE135B)=40:60时，并用胶的200％定伸应力，回弹性，硬度和耐热老化性能都较好，并用20－40份CPE135B能改善NBR耐3^#油性能；并用CPE135B提高了NBR并用胶的阻燃性。     

CPE／VPB并用硫化胶的性能研究

分别讨论了氯化聚乙烯与1,2—聚丁二烯的工艺相容性,并用比,填充体系,软化及增塑俸系对并用硫化胶另学性能的影响,以及该并用硫化胶的应力松弛特性及热氧稳定性等。     

结合橡胶对SBR/BR并用胶界面相互作用的影响

通过对采用不同结合橡胶控制工艺制备的SBR/BR并用胶进行界面相互作用分析,研究结合橡胶对SBR/BR并用胶界面相互作用的影响。结果表明,采用SBR控制结合橡胶工艺可以形成更多的结合橡胶,使填料得以均匀分散;采用分子链柔顺性较好的BR控制结合橡胶,有利于提高两相通过填料形成的相互作用,从而提高并用胶体系相容性。     

氯化聚乙烯橡胶/羧基丁腈橡胶并用胶相容性研究

采用三维溶解度参数法、差示扫描量热法和物理性能分析法研究不同并用比的氯化聚乙烯橡胶(CM)/羧基丁腈橡胶(XNBR)并用胶的相容性。结果表明:XNBR和CM的三维溶解度参数分别为17.61和19.91(J·cm-3)1/2,两种橡胶每一维度的溶解度参数均相差不大,不同并用比的并用胶均具有一定的相容性;随着XNBR用量的增大,并用胶物理性能改变,当XNBR用量为40~50份时,并用胶的物理性能变化趋势发生改变。     

研究高聚物共混物相结构形态的新方法及其在共混研究中的应用

高聚物共混物(橡/橡、橡/塑、塑/橡)各相的不饱和度多有差异,KMnO_4溶液中新生态氧[O]的氧化作用可使共混物中较不饱和的组分相着色较深;溶液中加少许硫酸可使显色反应时间由30min缩短到30s;采用单面定向的特殊染色方法可使切片厚度由毫米级减薄为微米级;新近开发的带有摄象机、闭路电视系统的彩色电视显微镜,是研究高聚物共混的理想仪器。新方法和新仪器已在实际科研生产中获得广泛应用。     

橡胶彩色电视显微镜（RCTVLM）新技术的开发及其应用

橡胶彩色电视显微镜(RCTVLM)新技术由橡胶、高聚物及共混材料形态快速检测技术和新型彩色电视显微镜(CTVLM)组成。快速检测技术包括:与橡胶(橡塑)制品性能、工艺密切相关的胶料炭黑分散度;高聚物共混物(橡/橡、橡/塑、塑/橡)形态;浅色胶料填料分散度的快速检测以及硫化胶磨耗指纹(磨纹图)的快速分析。新近开发的带有摄象机、闭路电视系统的彩色电视显微镜(CTVLM)是研究高聚物共混的理想仪器。新方法和新仪器已在实际科研生产中获得广泛应用。     

Use of modified poly(ϵ‐caprolactone) in the compatibilization of poly(ϵ‐caprolactone)/maize starch blends

In this work, the compatibilization of a poly(?‐caprolactone) with a number‐average molecular weight of 120,000 g/mol (PCL¹²⁰) and maize starch was investigated by the addition of a chemically modified poly(?‐caprolactone). Two types of blends were prepared by melt extrusion. In type A blends, low‐molecular‐weight compatibilizers were used: (1) a poly(?‐caprolactone) with a number‐average molecular weight of 10,000 g/mol that was reacted with maleic anhydride to obtain chains terminating in carboxylic groups and (2) low‐molecular‐weight poly(?‐caprolactone)s (number‐average molecular weights of 600 and 2000 g/mol) with one pendant carboxylic group within the chains. With these groups of blends, tensile testing and scanning electron microscopy demonstrated that the compatibilizers were generally effective in inducing a better dispersion for a 60/40 poly(?‐caprolactone)/maize starch blend with a compatibilizer, improving the mechanical properties in comparison with uncompatibilized blends. The blends with 30% starch were not improved by the addition of compatibilizer, and this may be related to the rheology of the blends during preparation. In type B blends, high‐molecular‐weight compatibilizers were prepared through the grafting of variable amounts of acrylic acid or maleic anhydride to PCL¹²⁰ chains. The best compatibilizer action was obtained with 0.7 wt % maleic anhydride grafted to PCL¹²⁰ because both the dispersion and mechanical properties were further improved in comparison with uncompatibilized blends and type A blends. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

超细全硫化粉末丁腈橡胶/二元共聚氯醚橡胶共混物的结构与性能

采用熔融共混工艺制备了超细全硫化粉末丁腈橡胶(UFPNBR)/二元共聚氯醚橡胶(ECO)共混物,研究了共混物的相态结构、动态力学性能、物理机械性能及老化性能,并与丁腈橡胶(NBR)/ECO共混物进行了对比.透射电镜观察表明,在UFPNBR/ECO体系中,UFPNBR为分散相,ECO为连续相;而在NBR/ECO体系中,ECO为分散相,NBR为连续相.动态力学性能分析结果显示在共混质量比不超过50/50时,UFPNBR/ECO共混物只存在1个玻璃化转变温度;当共混质量比超过50/50时分散相尺寸较大,出现2个玻璃化转变温度,而NBR/ECO始终存在2个玻璃化转变温度.加入适量的UFPNBR(不超过50份,质量)能降低UFPNBR/ECO共混物的压缩永久变形.与NBR/ECO共混物相比,UFPNBR/ECO共混物的脆性温度较低,耐老化性能更好,但物理机械性能稍差.     

TPU/PLA nanocomposites with improved mechanical and shape memory properties fabricated via phase morphology control and incorporation of multi-walled carbon nanotubes nanofillers

Shape memory polymer nanocomposites based on thermoplastic polyurethane (TPU)/polylactic acid (PLA) blends filled with pristine multi-walled carbon nanotubes (MWCNTs) and modified MWCNTs─COOH were fabricated by direct melt blending technique and investigated for its morphology, mechanical, thermal, electrical, and shape memory properties. Morphological characterizations by using transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM) revealed better dispersion of MWCNTs─COOH in the polymer blend, which is attributed to the improved interfacial interactions between the polymer blends and MWCNTs-COOH. Loading of the MWCNTs-COOH in the TPU/PLA blends resulted in the significant improvements in the mechanical properties such as tensile strength and elastic modulus and these effects are more pronounced on increasing the MWCNTs─COOH loading amount, when compared to the pristine MWCNTs filled system. Thermal analysis showed that the glass transition temperature of the blends increases slightly with increasing loading of both pristine and modified MWCNTs in the system. The resistance of nanocomposites decreased from 2 × 10¹² Ω to 3.2 × 10¹⁰ Ω after adding 3% MWCNTs─COOH. The shape memory performance tests showed that the enhancement of shape recovery by 252% could be achieved at 3% MWCNTs loading, when compared to that of TPU/PLA blends.     

Dispersion of a novel phenolic rigid organic filler in isotactic polypropylene matrix by solution-mixing and melt-mixing

A novel phenolic rigid organic filler (named KD) with a high melting point was dispersed in an isotactic polypropylene (iPP) matrix by solution-mixing and/or melt-mixing. A series of KD/iPP blends was prepared with or without addition of maleic anhydride-grafted polypropylene (MAPP) as a compatibilizer. Influences of MAPP and mixing methods on the filler dispersion were studied using polaried optical microscope (POM), scanning electron microscope (SEM) and tensile test. The filler particles are always inclined to form large irregular aggregates in the iPP matrix due to their significant differences in polarity and solubility in solvent. However, an iPP/MAPP/KD (PMK) blend containing filler particles with a quasi-spherical shape (~97.8 nm in diameter) and narrow particle size distribution (polydispersity index= 1.076) was successfully prepared by incorporating MAPP to reduce the interfacial tension and surface free energy between the dispersion phase and the continuous phase, and adopting a spray-drying method after solution-mixing to suppress the increase of the size of the dispersed phase during the removal of solvent.     

Effect of Xylene Formaldehyde Resins on Epoxy Resin Adhesive

The effect of some types of xylene formaldehyde on epoxy resin adhesive is studied. Xylene formaldehyde resin or modified xylene formaldehyde resins are mixed into liquid epoxy resin and curing properties of the blends, their adhesive properties and the dispersion state of xylene formaldehyde resin in cured adhesive film are examined. The results obtained are as follows.

1) Generally, by the addition of xylene formaldehyde resins, the degree of curing of blends are decreased, but pot life is prolonged, and tensile shear strength of steel bonds is increased.

2) It is observed that effects of the amount of xylene formaldehyde resins and curing condition on tensile shear strength vary with the kind of xylene formaldehyde resin, because of the difference in chemical structure of xylene formaldehyde resins and their reactivity to epoxy resin.

3) It is found that a limited region of compatibility, between 80 and 100 phr, exists for 100% xylene formaldehyde resin in epoxy resin. It is also found that joint strength is reduced with higher viscosity and molecular weight of 100% xylene formaldehyde resin in the case of 80 phr blends, and that these results have some relation to the dispersion state of xylene formaldehyde resin in epoxy resin, judging from the cured adhesive film observed under a phase contrast microscope.     

多单体接枝聚丙烯对PP/PA6共混物形态及力学性能的影响

用同向双螺杆挤出机制备了马来酸酐(MAH)、苯乙烯(St)多单体熔融接枝聚丙烯[PP-g-(St-MAH)],将其作为增容剂在Haake转矩流变仪上与PP/PA6共混得到PP/PA6/PP-g-(St-MAH)共混物,并对共混物的性能及结构进行了表征。结果表明,该增容剂明显改善了共混物的力学性能,当增容剂含量为15~20份时,共混物的冲击强度和拉伸屈服强度达最大值。采用扫描电子显微镜观察共混物试样断面的形态,发现分散相的粒径明显减小,且分散均匀。     

空心玻璃微珠增韧高密度聚乙烯的性能研究

采用玻璃微珠（GB）对高密度聚乙烯（HDPE）进行增韧改性。通过扫描电子显微镜、偏光显微镜和力学性能测试考察了偶联剂处理、基体韧性、玻璃微珠粒子用量、粒径大小和结晶等因素对HDPE/GB体系微观形态和性能的影响。结果表明,偶联剂可以明显改善空心玻璃微珠在基体中的分散,对于HDPE/GB体系,要求基体的最低冲击强度为5.0～5.5KJ/m2。玻璃微珠用量25%,粒径2.5μm时,冲击强度可达38.0kJ/m2。     

挤出加工方法对制备PP/PET原位微纤共混物微观形态的影响

分别使用双螺杆挤出机、配备不同结构螺杆或强剪切机头的单螺杆挤出机对聚丙烯(PP)/聚对苯二甲酸乙二醇酯(PET)进行熔融共混挤出,并用扫描电子显微镜观察了产物的微观形态。结果表明,使用双螺杆挤出机或使用配备三段式螺杆的单螺杆挤出机挤出PP/PET,只能制备出PET以球状形态均匀分散在PP连续相中的共混物,不含有任何微纤;使用配备有头部直槽混炼件的单螺杆挤出机挤出PP/PET,部分PET会形成短而粗的微纤;采用熔融挤出热拉伸淬冷法挤出PP/PET,可生产出微纤直径约为5 μm、长径比超过20的原位微纤共混物;采用强剪切机头及头部配备有直槽混炼件螺杆的单螺杆挤出机挤出PP/PET,可生产出微纤直径约为5~7 μm、长径比超过20的原位微纤共混物,且该方法操作简单、辅助设备少、具有工业可行性。