多种成核剂对PBS结晶及力学性能的影响

本文研究了滑石粉、TMB-5、碳酸钙、硫酸钙晶须、高岭土等五种成核剂对聚丁二酸丁二醇酯(PBS)结晶行为及力学性能的影响。偏光显微镜的观察结果显示了成核剂能细化PBS的球晶尺寸,提高球晶排列的规整度;热分析结果表明添加成核剂能提高PBS的结晶温度,加快PBS的结晶速率;结晶性能的改善又直接造成PBS力学性能的提高,其拉伸强度和冲击强度都有明显上升。五种成核剂中以滑石粉的效果最为突出,能使PBS的结晶温度上升11℃,拉伸强度提高了4.4MPa。     

三元乙丙橡胶硫化胶粉改性聚丙烯的研究

采用三元乙丙橡胶（EPDM）与EPDM硫化胶粉复合作为聚丙烯（PP）抗冲改性剂,研究了EPDM硫化胶粉和交联剂DCP用量对PP复合材料性能的影响。结果表明,PP复合材料的拉伸强度和弯曲强度随着硫化胶粉含量的增加而提高,冲击强度明显改善;而DCP用量增加对PP复合材料的拉伸强度和弯曲强度产生不利影响,少量DCP有助于提高PP复合材料的冲击强度;由DSC分析可知,硫化胶粉使PP熔体的结晶温度明显提高。     

一种新型聚丙烯成核剂的合成及表征

以邻苯二甲酸和异丙醇铝为原料,合成了新型的邻苯二甲酸羟基铝盐类聚丙烯成核剂(OXA)。利用热重分析、X射线衍射仪、差示扫描量热仪和偏光显微镜分别考察了成核剂的热稳定性及其对等规聚丙烯（iPP）的晶型、结晶行为和结晶形态的影响,同时,还考查了成核剂对iPP力学性能的影响。结果表明,OXA是一种有效的聚丙烯α晶型成核剂,当添加量为0.3 %（质量分数,下同）时,iPP的结晶温度可提高13.26 ℃,结晶度由纯iPP的52.49 %提高到58.37 %,同时可显著细化iPP球晶;也明显提高了iPP的拉伸和弯曲强度,拉伸强度由36.18 MPa提高为43.41 MPa,弯曲强度由46.19 MPa提高至50.89 MPa。     

碳酸钙/聚丁二酸丁二醇酯(PBS)可降解复合材料的力学及结晶性能

以生物降解塑料聚丁二酸丁二醇酯(PBS)为基材,以表面改性的CaCO3为填料制备出具有较好注塑性能的碳酸钙(CaCO3)/聚丁二酸丁二醇酯(PBS)可降解高填充复合材料。研究结果表明:改性剂的复配技术可以明显将复合材料的拉伸强度从30.39MPa提高至42.12MPa,复合材料的弹性模量也从1417MPa提高至1614MPa,分别提高了38.6%和14.0%。并通过对不同质量分数CaCO3的复合材料力学性能和热力学性能的研究与分析,为复合材料在不同领域的应用奠定一定的基础。通过对CaCO3/PBS复合材料的结晶性能研究发现,CaCO3在PBS中有一定的成核作用,在一定范围内随着CaCO3添加量的增加,能够促进PBS的成核结晶,明显提高结晶速度、结晶温度和结晶度,减小球晶尺寸,提高材料的拉伸强度。     

超支化乙二胺三嗪聚合物对PPC/PBS共混体系的增强改性研究

以超支化乙二胺三嗪聚合物（HBETP）为改性剂,采用熔融共混法制备了聚碳酸亚丙酯（PPC）/聚丁二酸丁二醇酯（PBS）/HBETP共混物;利用动态热机械分析仪、热失重分析仪、电子万能试验机、旋转流变仪、扫描电子显微镜等,对其热性能、力学性能、流变性能、断面形貌等进行了表征。结果表明,当HBETP含量为0.5 %（质量分数,下同） 时,PPC/PBS/HBETP共混物在韧性基本保持不变的情况下,拉伸强度提高幅度最大,由7.56 MPa提高到11.22 MPa,增幅为49.6 %;HBETP的加入可以提高PPC/PBS的相容性,且适当的含量会使PPC/PBS的拉伸强度提升。     

偶联剂对PBS/碳酸钙晶须复合材料力学性能与热稳定性的影响

用γ氨丙基三乙氧基硅烷（KH550）对碳酸钙晶须(CCW)表面处理后,与聚丁二酸丁二醇酯(PBS)混合,采用双螺杆挤出机熔融混合挤出造粒,制得PBS/CCW复合材料。结果表明,在1 %~5 %（质量分数,下同）的低添加量时,PBS/CCW复合材料的拉伸强度、弯曲强度和冲击强度分别增加了1 %~3.9 %、10 %~16 %和1 %~4.5 %;CCW添加量大于5 %时复合材料的拉伸强度与CCW添加量大于10 %时的冲击强度则分别随CCW添加量的增加而降低,而弯曲强度随CCW添加量的增加而逐渐提升; KH550表面处理CCW可以改善PBS/CCW复合材料的界面黏结性;CCW具有成核剂的作用, 使PBS的结晶温度提高了0.2 ℃,结晶度增加了0.2 %。     

原位增强PLA/PBS合金的微观形态及力学性能研究

以聚乳酸(PLA)和聚丁二酸丁二醇酯(PBS)为原料,过氧化二异丙苯(DCP)为增容剂,通过具有"扁平口模"的双螺杆挤出机进行熔融混合,利用热拉-骤冷成型工艺制备了一系列PLA/PBS合金。分别采用扫描电子显微镜(SEM)、广角X-射线衍射(WAXD)、差示扫描量热仪(DSC)和万能试验机测试研究了原位增强PLA/PBS合金的断面形态、结晶性能和力学性能。结果表明,PLA在PBS基体中形成了微纤增强形态,PLA微纤的形成未改变PBS基相的晶型;PLA微纤的形成使PLA/PBS合金的拉伸强度、弯曲强度与冲击强度分别较纯PBS提高了7.4%、28.9%和6.1%。随着DCP的加入,PLA微纤尺度降低且与PBS基体界面结合更紧密;当DCP的添加量为0.5%时,PLA/PBS合金的力学性能最佳。     

有机蒙脱土对PLA/PBS共混物相结构及性能的影响

通过熔融共混的方法制备了聚乳酸/聚丁二酸丁二醇酯/有机蒙脱土(PLA/PBS/OMMT)复合材料,研究了OMMT对不同组成的PLA/PBS共混物微观结构的影响,进而研究其对热性能、热稳定性以及拉伸性能的影响。微观结构结果表明,添加OMMT到PLA/PBS共混物中,能够降低分散相的尺寸,均化分散相尺寸分布,使PLA/PBS(50/50)共混物的双连续相结构改变为海-岛结构。DSC结果表明,PBS能够提高PLA的结晶能力,添加OMMT后,PLA相的冷结晶温度和熔点明显提高,结晶度达到39.5%,PLA的结晶形貌更加完善。TG结果表明,PBS能够提高PLA/PBS共混物热稳定性,添加OMMT后,进一步提高了共混物的热稳定性,起始分解温度提高至307.3℃。添加OMMT后,PLA/PBS/OMMT复合材料的拉伸性能得到提高,PLA/PBS/OMMT(80/20/1)复合材料的拉伸强度和断裂伸长率分别达到53.9 MPa和34.2%,在保证材料强度的前提下,得到了较好的延展性。     

交联改性聚丙烯的研究

以过氧化二异丙苯(DCP)为交联剂,苯乙烯(St)为助交联剂对聚丙烯(PP)进行交联改性。研究了交联剂(DCP)及交联剂(St)的用量对交联PP的力学及结晶性能的影响。结果表明,交联可以改善PP的性能。在DCP用量为0.05%,St为4%时,交联PP冲击强度达到3.83 kJ/m2,比纯PP提高了27%;拉伸强度由纯PP的36.02 MPa升高到37.22 MPa;交联PP的球晶尺寸减小,球晶间的界面模糊。     

过氧化物硫化体系下NBR/EVM共混胶耐热空气及耐油性能研究展

在过氧化物硫化剂DCP作用下,研究了NBR/EVM(EVM800 HV和EVM500 HV)共混比对硫化胶硫化特性、物理机械性能、热空气老化性能和热油老化性能的影响。结果表明,NBR/EVM硫化胶的交联密度随EVM用量增大而逐渐减小。对于NBR/EVM800 HV硫化胶,EVM800 HV用量不超过20份时,其拉伸强度基本不变,在EVM800 HV用量为20~40份时,其拉伸强度随EVM800 HV用量增大逐渐增大,由11.7 MPa增大至15 MPa,明显高于NBR/EVM500 HV硫化胶以及纯NBR硫化胶;100%定伸应力随EVM用量增大而逐渐增大,且NBR/EVM800 HV硫化胶增大更加显著,同时其100%定伸应力高于NBR/EVM500 HV硫化胶。并用EVM之后,NBR/EVM硫化胶的热空气稳定性变好。随着EVM500 HV用量的增大,NBR/EVM500 HV硫化胶的耐油性能逐渐变差;随着EVM800 HV用量的增大,NBR/EVM800 HV硫化胶的耐油性能逐渐变好,且优于NBR/EVM500 HV硫化胶。     

Morphology and mechanical properties of ethylene‐vinyl acetate rubber/polyamide thermoplastic elastomers

High performance thermoplastic elastomers based on ethylene‐vinyl acetate rubber (EVM) and ternary polyamide copolymer (tPA) were prepared through a dynamic vulcanization process in the presence of dicumyl peroxide (DCP). The morphology, crystallization, and mechanical properties of the EVM/tPA blends were studied. A phase transition of EVM/tPA blend was observed at a weight ratio of 60/40. The presence of EVM increased the melting enthalpy at the high temperature of tPA, ascribing to the heterogeneous nucleating effect of EVM. The tensile strength of EVM/tPA (70/30) blends was increased up to 20.5 MPa as the DCP concentration increased to 3.5 phr, whereas the elongation at break of the blends kept decreasing as the DCP concentration increased. The addition of ethylene‐acrylic acid copolymer (EAA) or maleic anhydride‐grafted EVM (EVM‐g‐MAH) to the EVM/tPA blends both induced finer dispersion of the EVM particles in the tPA phase and improvement in the tensile strength and elongation at break of the blends, which were ascribed to the compatibilization of EAA or EVM‐g‐MAH. Finally, a high performance EVM/tPA (70/30) thermoplastic elastomer with Shore A hardness of 75, tensile strength of 24 MPa, elongation at break of 361%, and set at break of 20% was obtained by adding 5 wt % of EVM‐g‐MAH and 3.5 phr DCP. It has great potential in automotive and oil pipeline applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polymerization conversion and structure of magnesium methacrylate in ethylene–vinyl acetate rubber vulcanizates

Ethylene–vinyl acetate rubber (EVM) filled with magnesium methacrylate (MDMA) was cured with dicumyl peroxide (DCP). The experimental results showed that the mechanical properties of MDMA/EVM vulcanizates were superior to those of high‐abrasion furnace carbon black/EVM vulcanizates. The tensile strength of the MDMA/EVM vulcanizate could reach 22.5 MPa and the tear strength was 83.5 kN/m, whereas its elongation at break remained over 300%, even when the MDMA content was 50 phr. FTIR analysis confirmed that polymerization of MDMA occurred under the initiation of DCP, and the polymerization conversion of MDMA decreased with the increase of MDMA content. When the MDMA content increased from 10 to 50 phr, the conversion of MDMA in EVM decreased from 68 to 20%. SEM and TEM observations indicated that 20 μm particles of MDMA powder changed into about 20 nm particles during the curing process, and the finer particles dispersed evenly in the EVM vulcanizates. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2379–2384, 2004     

拉伸形变作用下PLA/PBS增韧共混物力学性能研究

通过叶片挤出机对聚乳酸/聚丁二酸丁二醇酯（PLA/PBS）及添加剂进行塑化共混后制备复合增韧体系,研究不同PLA/PBS配比、挤出机转速以及添加剂种类对共混物力学性能的影响。结果表明,随着PBS含量的增加,PLA/PBS共混物的拉伸强度变化不大,而韧性明显提高;当叶片挤出机转速为75 r/min,改性剂邻苯二甲酸二仲辛酯(DCP)含量为0.05 %(质量分数,下同),马来酸酐接枝聚丙烯（PP-g-MAH)含量为1.5 %时,共混物具有最佳力学性能;PLA与PBS相容性较差,但叶片挤出机提供的拉伸力场迫使分散相分散均匀,尺度较小。     

Toughening modification of PLLA/PBS blends via in situ compatibilization

Biodegradable polymer blends consisting of poly(L ‐lactic acid) (PLLA) and poly(butylene succinate) (PBS) were prepared in the presence of dicumyl peroxide (DCP). The effects of DCP content on the mechanical properties, thermal and rheological behavior, phase morphology as well as the toughening mechanism of the blends were investigated. The notched Izod impact strength of PLLA/PBS (80/20) blend significantly increased after the addition of 0.05–0.2 phr DCP, but the strength and modulus monotonically decreased with increasing DCP content. PBS acted as a nucleating agent at the environmental temperature below its melting temperature and accelerated the crystallization rate of PLLA but had little effect on its final degree of crystallinity. The degree of crystallinity of PBS and the cold crystallization ability of PLLA gradually reduced with increasing DCP content. The addition of DCP induced an increase in viscosity of the blends at low frequencies as well as finer dispersion of PBS particles and better interfacial adhesion between PLLA and PBS, indicating the in situ compatibilization occurred between the two components. The optical clarity of PLLA/PBS blends was significantly improved after the addition of DCP, which was in accordance with the crystallization behavior and phase structure of the blends. POLYM. ENG. SCI., 2009. © 2008 Society of Plastics Engineers     

橡胶型乙烯－醋酸乙烯共聚物配方及老化性能研究

研究了橡胶型乙烯－醋酸乙烯共聚物（ＥＶＭ）的配方及热氧老化性能。试验结果表明：ＥＶＭ具有优异的热空气老化性能，经１７５℃×７２ｈ老化后仍有很高的拉伸强度和扯断伸长率保持率；需采用过氧化物进行硫化，同时并用适量的三烯丙基异氰脲酸酯可以显著改善ＥＶＭ的压缩永久变形性能；它是一种典型非自补强性橡胶．需加入适量的补强填充剂；聚酯增塑剂可以在一定程度上降低ＥＶＭ的硬度，而对老化性能影响不大；防老剂ＲＤ可赋予胶料更优良的热空气老化性能和耐水解性能。     

Structure and properties of nylon 1010/ethylene‐vinyl acetate rubber–based dynamically vulcanized thermoplastic elastomers filled with SiO2

Dynamically vulcanized Nylon 1010/ethylene‐vinyl acetate rubber (EVM)/SiO₂ nanocomposites were prepared. Maleic anhydride grafted ethylene‐vinyl acetate copolymer (EVA‐g‐MA) and nano‐silica (SiO₂) was used as a compatibilizer and a filler, and silane coupling agent (KH550, 3‐triethoxysilylpropylamine) was used to improve the dispersion of SiO₂ in the nanocomposites. The nanocomposites were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), dynamic mechanical analysis (DMA), differential scanning calorimeter (DSC), and rheology analysis and mechanical properties test. SEM and AFM images showed that the compatibility between Nylon 1010 and EVM was improved by adding the compatibilizer. An increase in SiO₂ content and the addition of the compatibilizer led to an increase in the tensile strength of the nanocomposite. A nanocomposite based on Nylon 1010/EVM/DCP (30/70/0.8) with tensile strength of 16.3 MPa and elongation at break of 180% was obtained by the addition of 15 phr EVA‐g‐MA and 40 phr SiO₂. The non‐isothermal crystallization processes of Nylon/EVM blend were investigated by DSC. It was observed that EVM rubber could act as heterogeneous nuclei for Nylon which was more effective in Nylon/EVM/DCP blend than in Nylon/EVM blend. POLYM. ENG. SCI., 55:581–588, 2015. © 2014 Society of Plastics Engineers     

Properties of EVM vulcanizates reinforced by in situ prepared sodium methacrylate

Ethylene–vinyl acetate copolymer (EVM) vulcanizates with good mechanical properties and high transparency were obtained using sodium methacrylate (NaMAA) as a reinforcing agent. Sodium methacrylate was in situ prepared through the neutralization of sodium hydroxide (NaOH) and methacrylic acid (MAA) in an EVM and used to reinforce the EVM cured by dicumyl peroxide (DCP). Different factors such as the DCP content, NaMAA content, and the mol ratio of NaOH/MAA were included to study their effects on the mechanical properties, optical properties, stress‐relaxation behavior, and crosslink structure of the EVM vulcanizates. The rheological behavior of the EVM compounds was also investigated and compared with that of the high abrasion furnace carbon black (HAF)/EVM compounds. The experimental results show that with an increase of the NaMAA content the curing rate index (C_R) of the EVM compounds is greatly speeded up, while the Mooney viscosities of the compounds remain nearly unchanged. The mechanical properties and optical properties of the NaMAA‐reinforced EVM vulcanizates depend on the NaMAA content and the mol ratio of NaOH/MAA. The formulation of DCP of 3 phr and a NaOH/MAA mol ratio of 1.0 is recommended for the EVM vulcanizate with high mechanical properties. At a given NaOH/MAA mol ratio of 1.0, all the EVM vulcanizates are transparent and the light transmission is over 76% in the NaMAA content range of 10–50 phr. The NaMAA/EVM vulcanizates show faster stress relaxation and more obvious stress‐softening effects than those of the HAF/EVM vulcanizates. Crosslink density analysis indicated that the EVM vulcanizates contain both covalent and ionic bonds. The ionic crosslink densities greatly increase with an increasing NaMAA content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2192–2200, 2003     

Study on the properties of ethylene‐vinyl acetate rubber vulcanizate filled with superfluous magnesium hydroxide/methacrylic acid

Ethylene‐vinyl acetate rubber (EVM) vulcanizates cured by dicumyl peroxide (DCP) with excellent mechanical properties were obtained by adding superfluous magnesium hydroxides (MH)/methacrylic acid (MAA). Different factors such as the DCP content and MH content were investigated to reveal their effects on the properties of the MH/MAA‐filled EVM vulcanizates. The formulation of DCP of 2 phr, MH of 60 phr, and MAA of 5 phr is recommended for the EVM vulcanizates with excellent mechanical properties. The stress relaxation and stress softening behavior of MH/MAA‐filled EVM vulcanizates were studied. The stress relaxation and stress softening became faster and more obvious with increasing MH content. The hot air aging resistance of EVM vulcanizates filled with different fillers such as silica and high abrasion furnace were compared, and the MH/MAA‐filled EVM vulcanizates had the best aging resistance at 40‐phr filler content. The MH/MAA‐filled EVM vulcanizates had excellent flame retardancy due to the high MH content. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

硅橡胶/EVM共混物性能的研究

考察了硅橡胶／橡胶型乙烯醋酸乙烯酯共聚物（ＥＶＭ）用量比、过氧化物品种及其用量、相容剂等因素对硅橡胶／ＥＶＭ共混物物理性能的影响。实验结果表明，硅橡胶／ＥＶＭ用量比大于１时，共混物强度性能主要受硅橡胶的影响；硫化剂选用ＤＣＰ较为合适；共混物的性能低于两种单一胶种性能的加和值，两胶种相容性较差；以乙烯基三乙氧基硅烷接枝ＥＶＭ作为相容剂，对该共混体系两相间的相容性有一定的改善。     

聚丁二酸丁二醇酯泡沫材料的制备

采用模压化学发泡的方法制备了可生物降解的聚丁二酸丁二醇酯(PBS)泡沫材料,并研究了其性能.结果表明,采用过氧化二异丙苯(DCP)作交联剂辅以三羟基甲基丙烷三甲基丙烯酸酯(TMPTAM)作助交联剂能明显提高PBS的黏度,使其具有较高的熔体强度.当DCP用量为4～5份时,泡沫材料泡孔均匀且密度适中,同时,PBS泡沫材料在...