改性NR对PVC增韧研究

研究了改性天然橡胶(NR)的性质对聚氯乙烯(PVC)硬质材料的增韧作用。发现改性NR的主链结构、支链的极性、NR含量等是影响改性NR/PVC共混材料的冲击强度的主要因素。交联型改性NR对PVC有显著的增韧效果,其共混材料的冲击强度高达60kJ/m~2,比纯PVC材料高15倍以上。扫描电子显微镜照片显示交联型改性NR/PVC共混材料的冲击断面布满均匀细密的“须根”,无裂缝,无NR粒子剥离现象。透射电子显微镜分析显示,交联型改性NR/PVC的相界面有模糊的过渡层,说明二者部分相容。     

氯丁橡胶/天然橡胶阻燃橡胶材料的制备及性能

将氯丁橡胶(CR)和天然橡胶(NR)以不同共混比加入不同的阻燃体系,探究了共混材料的综合力学性能和阻燃性能等,以期选出性能最优的CR/NR共混比和性能最佳的阻燃体系。结果表明,随着CR用量增加,CR/NR共混材料的拉伸强度和拉断伸长率下降,定伸应力和硬度增加,耐老化性能和阻燃性能提高,当m(CR)/m(NR)=60/40时,老化后的拉伸强度高于老化前。加入增容剂环氧化天然橡胶(ENR)能明显改善CR/NR的相容性,提高材料的力学性能。当m(氢氧化铝)/m(硼酸锌)/m(红磷)=50/20/10时,阻燃体系能够在不降低共混材料力学性能的基础上,较好地提高共混材料的阻燃性能。     

氯化乙丙橡胶增容PVC/SBS共混体系的研究

以氯化乙丙橡胶(CEPDM)为相容剂,研究了SBS对PVC的共混增韧改性。结果表明CEPDM能明显改善SBS与PVC的相容性,使共混物中SBS颗粒尺寸明显减小,分布更均匀,共混物的t_g内移,常温和低温下缺口冲击强度增大。当PVC/SBS/CEPDM为80/20/6(质量比)时,共混物的常温缺口冲击强度为56.3kJ/m~2,低温(-20℃)缺口冲击强度为32.4kJ/m~2。     

顺酐化聚苯乙烯对PVC/SEBS共混物的增容作用

以顺酐化聚苯乙烯(PS-g-MAH)为增容剂,研究了苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)对聚氯乙烯(PVC)的共混增韧改性,讨论了该共混物在常温、低温下的力学性能及动态力学性能。结果表明,PS-g-MAH能明显改善SEBS与PVC的相容性,使PVC/SEBS共混物中分散相颗粒尺寸明显减小,分布更均匀,共混物的玻璃化转变温度内移,常温和低温下缺口冲击强度增大。当PVC/PS-g-MAH/SEBS(质量比)为75/6/25时,共混物的常温缺口冲击强度为50.6 kJ/m2,低温(-20℃)缺口冲击强度为29.8 kJ/m2。     

氯化聚丙烯对PP/PVC共混物性能的影响

以氯化聚丙烯(CPP)为增容剂,探讨了CPP不同含量下PP/PVC体系的力学性能、相容性、流变性能以及对应的微观结构,并与氯化聚乙烯(CPE)增容剂进行了比较。发现添加5份CPP可明显改善PP和PVC两相界面相容性,与PP/PVC体系相比,拉伸强度提高了61%,无缺口冲击强度提高了100%。此时CPP还起到了一定的增塑作用,共混体系加工性能较好。与CPE相比,含有CPP的共混体系拉伸强度较高。     

天然橡胶/氯化聚氯乙烯热塑性弹性体的性能与结构

采用动态硫化法制备天然橡胶(NR)/氯化聚氯乙烯(CPVC)热塑性弹性体(TPV),并研究甲基丙烯酸缩水甘油酯(GMA)/苯乙烯(St)双单体熔融接枝NR[NR-g-(GMA-co-St)]与白炭黑复配增容补强NR/CPVC TPV的物理性能、耐溶剂性能和微观形态结构。结果表明:当NR-g-(GMA-co-St)和白炭黑的用量分别为7和3份时,交联NR分散相在CPVC基体中的分散度和均一性得到明显改善,相界面的结合强度显著提高,达到良好的复配增容补强效果。与未改性NR/CPVC TPV相比,改性NR/CPVC TPV的拉伸强度、拉断伸长率和撕裂强度增大,耐溶剂性能明显改善。     

环氧类增容剂反应增容PLA/PBAT共混体系的研究

以环氧类增容剂(REC)为增容剂,采用双螺杆挤出机熔融共混制备聚乳酸(PLA)/聚对苯二甲酸己二酸丁二醇酯(PBAT)共混物。研究了增容剂对共混体系微观结构、力学性能和热性能的影响。结果表明,添加适量REC可以提高PLA与PBAT的相容性,改善PLA/PBAT共混体系的综合力学性能;REC用量为1.4份时共混体系呈现出良好的相容性,此时共混物冲击强度由268 kJ/m2增加到621 kJ/m2、断裂伸长率提高由222 %增加到357 %。     

氯化胶粉/聚氯乙烯共混物性能的研究

以氯化胶粉(CGRT)和聚氯乙烯(PVC)为主要原料制备CGRT/PVC共混物,并通过试验研究CGRT用量和氯质量分数、增塑剂DOP用量以及氯化聚丙烯改性CGRT对其物理性能的影响。结果表明:CGRT用量为20份且氯质量分数为0.08左右、增塑剂DOP用量为30～40份时,CGRT/PVC共混物的物理性能较佳;与CGRT/PVC共混物相比,改性CGRT/PVC共混物的拉伸强度、拉断伸长率、撕裂强度和冲击强度均有提高。     

ABS/HIPS共混材料的改性研究

研究了(丙烯腈/丁二烯/苯乙烯)共聚物(ABS)与高抗冲聚苯乙烯(HIPS)质量比对ABS/HIPS共混材料力学性能和加工流动性的影响,并着重对质量比分别为80/20和70/30的两种ABS/HIPS共混材料进行了改性研究。结果表明,氯化聚乙烯(PE-C)、(苯乙烯/丁二烯/苯乙烯)嵌段共聚物(SBS)和K树脂对ABS/HIPS共混材料有不同程度的增容增韧改性作用。如采用9份PE-C与3份SBS并用改性的ABS/HIPS(70/30)共混材料的拉伸强度为27.04MPa,冲击强度为32.60kJ/m2,比改性前约提高2.7倍。转矩流变仪分析表明,PE-C、SBS和K树脂改性的ABS/HIPS共混材料加工流动性和稳定性良好。维卡软化温度测试表明,改性后ABS/HIPS共混材料的耐热性能略有降低,但影响不大。扫描电子显微镜照片清晰反映出改性后ABS与HIPS两相的相容性得到了改善。     

POM／TPU共混物的力学性能和摩擦磨损性能研究

采用双螺杆挤出熔融共混的方法制备了聚甲醛(POM)和热塑性聚氨酯弹性体(TPU)/增容剂Z共混物.考察了共混物的力学性能、摩擦磨损性能,并通过扫描电子显微镜(SEM)观察其微观形态结构以及磨损表面形貌.结果表明:加入增容剂z可以使共混体系的相容性得到改善,提高了缺口冲击强度;当TPU的质量分数为30份时,缺口冲击强度达到13.8 kJ/m2,比纯POM提高了126%;共混物的摩擦磨损性能下降,随着TPU的用量的增加共混物的摩擦因数呈现先减小后增大趋势,而磨损量随之增大.     

Toughness enhancement of poly(lactic acid) by melt blending with natural rubber

Rubber toughened poly(lactic acid) (PLA) was prepared by blending with natural rubber (NR)‐based polymers. The blends contained 10 wt % of rubber and melt blended with a twin screw extruder. Enhancement of impact strength of PLA was primarily concernced. This study was focused on the effect of rubber polarity, rubber viscosity and molecular weight on mechanical properties of the blends. Three types of rubbers were used: NR, epoxidized natural rubber (ENR25 and ENR50), and natural rubber grafted with poly(methyl methacrylate) (NR‐g‐PMMA). Effect of viscosity and molecular weight of NR, rubber mastication with a two‐roll mill was investigated. It was found that all blends showed higher impact strength than PLA and NR became the best toughening agent. Viscosity and molecular weight of NR decreased with increasing number of mastication. Impact strength of PLA/NR blends increased after applying NR mastication due to appropriate particle size. DMTA and DSC characterization were determined as well. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Preparation and Electron Beam Irradiation of PVC/ENR/CNTs Nanocomposites

Poly (vinyl chloride), PVC/epoxidized natural rubber blend, ENR/carbon nanotubes, CNTs nanocomposites were prepared using melt intercalation and solution blending methods. In both preparation methods PVC: ENR: CNTs ratios were fixed at 50:50:2, while the 50/50 PVC/ENR blend without the addition of CNTs was used as control. The PVC/ENR/CNTs nanocomposites were exposed to electron beam (EB) irradiation at doses ranging from 0–200 kGy. The effects of two different preparation methods on the tensile properties, gel fraction and morphology of the PVC/ENR/CNTs nanocomposites were studied. Prior to EB irradiation, the addition of 2 phr of CNTs caused a drop in the tensile strength (Ts) of the 50/50 PVC/ENR blend, implying poor distribution of CNTs in the PVC/ENR blend matrix. However upon EB irradiation, the nanocomposites prepared by the melt blending method exhibited higher values of Ts as compared to the neat PVC/ENR blend due to occurrence of radiation-induced cross-linking in the PVC/ENR blend matrix. Transmission electron microscopy (TEM) images proved that a better dispersion of CNTs in PVC/ENR blend matrix can be achieved by melt intercalation compared to solution blending and the dispersion of CNTs was improved by irradiation. Scanning electron microscopy (SEM) results showed a distinct failure surface with formation of rough structure for the irradiated nanocomposites, which explains the higher values of tensile properties compared to the non-irradiated nanocomposites.     

Compatibilization of poly(lactic acid)/epoxidized natural rubber blend with maleic anhydride

The objective of this work was to determine the compatibilization effect of different concentrations of maleic anhydride (MA) in poly(lactic acid) blended with epoxidized natural rubber (PLA/ENR). ENR-grafted MA [ENR-g-MA] was synthesized using four concentrations of MA: 0.15, 0.30, 0.45, and 0.60 phr. Using an internal mixer, binary (PLA/ENR, PLA/ENR-g-MA) and ternary (PLA/ENR/ENR-g-MA) polymer blends were prepared with a constant rubber content of 10 wt %. ENR impaired the mechanical properties of PLA, perhaps due to the relatively large size of the rubber particles. The compatibilization effect of MA was evaluated from the results of impact strength testing. ENR-g-MA was a toughening agent for PLA when the concentration of MA was in the range of 0.30–0.60 phr. MA increased miscibility between PLA and ENR. This effect was indicated in the blends by reductions in rubber particle size, the glass transition temperature of PLA, and the α-transition temperatures of PLA and ENR. In the binary polymer blends, the MA concentration in ENR-g-MA that produced the optimal mechanical properties of PLA was 0.60 phr. In the ternary blends, mechanical properties of PLA did not improve at any concentration of MA in ENR-g-MA. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48297.     

Curing Characteristics and Aging Properties of Natural Rubber/Epoxidized Natural Rubber and Cellulose II

In this work, natural rubber (NR) and regenerated cellulose (cel II) latexes were co-coagulated and to the mixture epoxidized natural rubber (ENR) was added on a two-roll mill. The cellulose content was fixed at 20 phr while ENR content varied from 0 to 75 phr. The influence of ENR was studied through the cure characteristics, aging and dynamic-mechanical properties. The aging provides nanocomposites with better solvent resistance and increased tensile strength at ENR content of 25 phr. The results suggest that a new type of light-colored nanocomposites were obtained, which presented high mechanical performance and resistance to solvents.     

环氧化天然橡胶共交联改性EPDM/NR共混物的性能

将三元乙丙橡胶(EPDM)与环氧化天然橡胶(ENR)共交联改性后,再与天然橡胶(NR)共混,考察了ENR共交联改性EPDM/NR共混胶的硫化特性、硫化胶的物理机械性能、溶胀指数和耐热空气老化性能,并对该硫化胶进行了差示扫描量热分析。结果表明,EPDM经过ENR共交联改性后与NR共混,ENR共交联改性EPDM/NR共混胶的交联程度明显提高,各相达到了同步交联,硫化胶的综合性能得到了显著改善。     

Thermoplastic natural rubber based on polyamide‐12: Influence of blending technique and type of rubber on temperature scanning stress relaxation and other related properties

Thermoplastic natural rubber based on polyamide‐12 (PA‐12) blend was prepared by melt blending technique. Influence of blending techniques (i.e., simple blend and dynamic vulcanization) and types of natural rubber (i.e., unmodified natural rubber (NR) and epoxidized natural rubber (ENR)) on properties of the blends were investigated. It was found that the simple blends with the proportion of rubber ～ 60 wt % exhibited cocontinuous phase structure while the dynamically cured blends showed dispersed morphology. Furthermore, the blend of ENR exhibited superior mechanical properties, stress relaxation behavior, and fine grain morphology than those of the blend of the unmodified NR. This is attributed to chemical interaction between oxirane groups in ENR molecules and polar functional groups in PA‐12 molecules which caused higher interfacial adhesion. It was also found that the dynamic vulcanization caused enhancement of strength and hardness properties. Temperature scanning stress relaxation measurement revealed improvement of stress relaxation properties and thermal resistance of the dynamically cured ENR/PA‐12 blend. This is attributed to synergistic effects of dynamic vulcanization of ENR and chemical reaction of the ENR and PA‐12 molecules. Furthermore, the dynamically cured ENR/PA‐12 blend exhibited smaller rubber particles dispersed in the PA‐12 matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

硅藻土/天然橡胶复合材料的性能研究

利用环氧化天然胶乳作为硅藻土的界面改性剂,制备了硅藻土/天然橡胶复合材料,通过无转子流变仪、电子万能材料试验机和橡胶动态压缩生热仪,研究了复合材料的硫化特性,物理机械性能和温升特性。结果表明,硅藻土/天然橡胶复合材料的焦烧与正硫化时间随着硅藻土含量的增加,先增后减;最大与最小扭矩随硅藻土含量的增加而增加;硅藻土/天然橡胶复合材料的拉伸与撕裂强度均有提高,当硅藻土含量为4phr时,拉伸强度最高,为28.5MPa;当硅藻土的含量为2phr时,撕裂强度最高,为37.9N/mm;由于硅藻土的加入,材料的内生热显著降低。     

Room temperature and low temperature toughness improvement in SAN/ASA blends by blending with CPE,HNBR, and BR

Styrene‐acrylonitrile copolymer (SAN)/acrylonitrile‐styrene‐acrylate terpolymer (ASA) blends (75/25, wt/wt) was toughened by blending with impact modifiers including chlorinated polyethylene (CPE), hydrogenated nitrile butadiene rubber (HNBR), and butadiene rubber (BR) and the impact property was tested at four temperatures (–30, ?15, 0, and 25 °C). The combination of CPE and HNBR was imported to toughen the SAN/ASA blends, indicating that CPE and HNBR had similar toughening effect at room temperature but HNBR exhibited a better performance at low temperature. When a little HNBR was substituted by BR, the impact strength improved dramatically with the total content of impact modifiers keeping at 30 phr. After 15 phr CPE, 10 phr HNBR and 5 phr BR were employed into blends together, the impact strength reached to a peak of 14 kJ/m² at ?30 °C while the impact strength of the blends individually toughened by 30 phr CPE or 30 phr HNBR was 5 or 12 kJ/m², respectively. The toughening mechanism showed that the low glass‐transition temperature (–108 °C) of BR and the compatibilization between BR and matrix accounted for the improvement of toughness. Simultaneously, scanning electron microscopy, dynamic mechanical analysis, flexural and tensile properties, heat distortion temperature, and Fourier transform infrared spectroscopy were measured. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45364.     

Pervaporation of acetone‐chlorinated hydrocarbon mixtures through polymer blend membranes of natural rubber and epoxidized natural rubber

Transparent nonporous membranes were prepared by blending natural rubber (NR) with epoxidized NR (ENR). These blend membranes were evaluated for the selective separation of chlorinated hydrocarbons from acetone. The flux and selectivity of the membranes were determined both as a function of the blend composition and feed mixture composition. Results showed that polymer blending method could be very useful to develop new membranes with improved permselectivity. Pervaporation properties could be optimized by adjusting the blend composition. NR/ENR 70/30 and NR/ENR 30/70 composition showed a decrease in flux and selectivity, whereas the 50/50 composition showed increased flux and increased selectivity. Chlorinated hydrocarbons permeated preferentially through all the tested membranes. The feed mixture composition also strongly influenced the pervaporation characteristics of the blend membranes. Permselectivity was found to depend on the molecular size of the penetrants. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2365–2379, 1999     

One‐step latex compounding method for producing composites of natural rubber/epoxidized natural rubber/aminosilane‐functionalized montmorillonite: enhancement of tensile strength and oil resistance

Montmorillonite (Mt) was intercalated with cetyltrimethylammonium bromide and functionalized with three types of aminosilane (3‐aminopropyltrimethoxysilane, n‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane and 3‐[2‐(2‐aminoethylamino)ethylamino]propyltrimethoxysilane). The modified Mt was compounded with natural rubber (NR)/epoxidized natural rubber (ENR) via one‐step latex compounding. The effect of the modified Mt content on the oil resistance and mechanical properties of the NR/ENR/modified Mt composites was investigated. The X‐ray diffraction patterns of the composites showed partial intercalation/exfoliation of the modified Mt in the rubber matrix. Cryogenic fracture and X‐ray fluorescence results revealed highly dispersed modified Mt in the composites in the presence of 10 phr ENR. All three aminosilane groups slightly improved the oil resistance, with the long‐alkyl‐length group producing the greatest improvement. The addition of a small amount of modified Mt improved both oil resistance and tensile strength by increasing in the average diffusion path length in the NR matrix and enhancing the interaction between the modified Mt and the epoxide groups in ENR. The addition of 1.0 phr of modified Mt increased the tensile strength by 18% and decreased the elongation at break by 12% compared with a neat NR/ENR blend. © 2017 Society of Chemical Industry