共查询到20条相似文献,搜索用时 15 毫秒
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To produce biodegradable poly(butylene succinate) (PBS) foam by compression molding, high viscosity PBS was prepared with dicumyl peroxide (DCP) as a crosslinking agent and trimethylolpropane trimethacrylate (TMPTMA) as a curing coagent by crosslink method. The influences of various factors on the foaming process and the properties of PBS foams were investigated. The results show that the use of DCP and TMPTMA simultaneously can effectively increase the melt viscosity of PBS. Zinc oxide/zinc stearate was used to reduce the thermal decomposition temperature of the blowing agent azodicarbonamide, which can balance well the vulcanization of PBS and the decomposition of blowing agent. Finally, closed‐cell PBS foams with degradable property have been successfully prepared by a traditional chemical compression molding foaming way. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
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过氧化物硫化EPDM发泡材料的研制 总被引:1,自引:1,他引:1
探讨了采用过氧化物硫化的EPDM发泡材料的配方设计和工艺。EPDM发泡材料的优化配方为 :EPDM [或EPDM/甲基乙烯基硅橡胶 (并用比 90 /10 )并用体系 ] 10 0 ;2 #气相法白炭黑 5 0 ;30 #机油 10 ;乙二醇 3;硫化剂DCP 2~ 3;氧化锌 8;发泡剂AC 8;调节剂A 1;调节剂B 0 5。EPDM的塑炼辊温为( 2 3± 5 )℃ ,胶料的混炼辊温为 60~ 70℃。混炼后压出的胶片密实 ,无气泡和杂质 ,表面光滑平整。装模用的胶片完整且厚度均匀一致。胶料的硫化条件为 :一段 170℃× ( 9~ 10 )min ;二段 170℃× 10min。优化配方的发泡材料物理性能较好 相似文献
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硅橡胶/三元乙丙橡胶泡沫合金的研制 总被引:7,自引:2,他引:5
研究了硅橡胶/三元乙丙橡胶(Q/EPDM)共混,发泡的配方与成型工艺,对补强剂,发泡剂,硫化剂,成型温度,时间等因素对泡沫材料的密度硬度等性能的影响进行了研究。 相似文献
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Ethylene–propylene–diene terpolymer foam was prepared by two different processing routes. The microstructure and mechanical properties of the foams with wide relative density ranging from 0.11 to 0.62 have been studied via scanning electron microscopy and mechanical testing, respectively. Scanning electron microscopy shows that the foam with lower relative density has a unique bimodal cell size structure, which the larger cells inlay among the smaller cells, while the foam articles with higher relative density have thicker cell walls with few small cells. The compressive stress–strain curves show that the foam articles with lower relative density have three regimes: linear elastic, a wide slightly rising plateau, and densification, while the foam articles with higher relative density have only two regimes: the longer linear elastic and densification. The relative modulus increases with the increase in the relative density. The contribution of the gas trapped in the cell to the modulus could be neglected. The energy absorbed per unit volume is relationship with the permitted stress and the relative density. The efficiency and the ideality parameter were evaluated from the compressive stress–strain plots. The parameters were plotted against stress to obtain maximum efficiency and the maximum ideality region, which can be used for optimizing the choice for practical applications in cushioning and packaging. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
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Ethylene–propylene–diene terpolymer (EPDM) was modified by bromination reaction. Blending the resulting brominated EPDM with natural rubber (STR5L) and blending the unmodified EPDM with STR5L at various compositions were carried out. The rheological properties of the blends were investigated using a capillary extrusion. Shear flow curves of the pure rubbers and their blends illustrated the pseudoplastic property as shear thinning behavior with a power law index n < 1. True shear viscosity of all blends showed the negative deviation in relation to their additive values. Rheological behavior and two Tg's found from the DSC thermograms at all blend compositions indicated blend incompatibility for both sets of blends. The incompatibility of the vulcanized blends was also found by measuring the spin–spin relaxation time T2 by pulsed NMR. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 837–847, 2003 相似文献
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研究了复合交联剂、复合发泡剂及其用量对PP/EPDM复合材料力学性能的影响。实验结果表明:PP/EPDM(70∶30)复合材料经过微孔发泡后,其力学性能达到PP/EPDM(50∶50)复合材料力学性能;微孔发泡技术的应用可减少复合材料中EPDM用量,达到降低成本的目的。 相似文献
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研究了硅橡胶/三元乙丙橡胶(Q/EPDM)配方对泡沫合金的结构、密度、硬度、压缩、拉伸、应力松驰等力学性能的影响规律。研究表明:EPDM含量增加,泡沫合金的硬度、压缩强度、拉伸强度性能提高,而压缩永久变形、应力松驰性能下降。 相似文献
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考察了过氧化二异丙苯/N,N-二亚硝基五次甲基四胺(DCP/H)、2,5-二甲基-2,5-二叔丁基过氧化己烷/偶氮二甲酰胺(双二五/AC)和过氧化苯甲酰(BPO)/AK 3种硫化发泡体系及助交联剂TAIC对硅橡胶泡沫材料力学性能和压缩应力松弛性能以及泡孔结构的影响。结果表明,DCP/H硫化发泡体系的力学性能和应力松弛性能优于双二五/AC和BPO/AK,添加适量助交联剂TAIC有助于进一步降低硅橡胶泡沫材料的应力松弛性能。扫描电镜(SEM)观察发现,DCP/H硫化发泡体系对应的硅橡胶发泡材料泡孔较小且分布均匀,当加入适量的助交联剂TAIC后,硅橡胶泡沫材料的泡孔更加细小均匀。 相似文献
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In this article, the morphology, crystallization, and rheological behaviors of polypropylene (PP)/ethylene‐propylene‐diene terpolymer (EPDM) binary blend and PP/EPDM/calcium carbonate nanoparticles (nano‐CaCO3) ternary blend were investigated. Two processing methods, i.e., direct extrusion and two‐step extrusion, were employed to prepare the PP/EPDM/CaCO3 blend. The influence of EPDM and nano‐CaCO3 respectively on phase morphology and properties of PP/EPDM blend and PP/EPDM/CaCO3 blend were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic rheometer. The crystallinity and crystallization temperature of PP/EPDM blend were improved in comparison to pure PP due to addition of EPDM, but kept invariable with the increased EPDM loading. As the EPDM content was increased, the mobility of PP molecular chains was weakened. Compared with direct extruded blend, less and finer nano‐CaCO3 was dispersed in matrix of two‐step extruded blend. Accordingly, the increased nano‐CaCO3 in matrix gave rise to a weaker increment in crystallinity and crystallization temperature of two‐step extruded blend, and a later platform of tanδ curve. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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Silicone rubber foam was prepared through crosslinking with electron beam irradiation and foaming by the decomposing of blowing agent azobisformamide (AC) in hot air. The crosslinking and foaming of silicone rubber was carried out separately, which was different from the conventional method of chemical crosslinking and foaming. After foaming, the silicone rubber foam was irradiated again to stabilize the foam structure and further improve its mechanical properties. The effects of irradiation dose before and after foaming, and the amount of blowing agents on the structure and properties of silicone rubber foam were studied. The experimental results show that with the increase of AC content, the average cell diameter of silicone rubber foam increases a little, the foam density decreases to a minimum value when AC content is 10 phr. With the increase of irradiation dose before foaming from 10 to 17.5 kGy, the cell nucleation density of silicone rubber foam increases, the average cell diameter decreases, and the foam density increases. With the increase of irradiation before foaming, the tensile strength, tensile modulus, and the elongation at break of the silicone rubber foam increase. Through irradiation crosslinking again after foaming, the foam density is decreased and the mechanical properties of silicone foam are further improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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Rafael Barbosa Guilherme Eduardo de Oliveira Blanco Alexander Hiroshi Kasama Diego Alexandre Belmonte Barbosa Rafael de Almeida Peçanha José Donato Ambrósio 《应用聚合物科学杂志》2021,138(14):app50140
This study was committed to the characterization of the rheological, thermal, mechanical, and morphological properties of ethylene-propylene-diene monomer (EPDM)/silicone rubber (SR) blends. These blends are a potential new class of materials for the insulation of circuits and electrical components that actuate in environments with high heat generation. The blends were produced in a torque rheometer with a Banbury type rotor, varying the concentration of EPDM and SR. Results obtained by capillary rheometry were applied to three theoretical models to analyze the phase inversion threshold, which was confirmed by scanning electron microscopy images. Such analyzes were important to describe the consequence of phase inversion on the evaluated properties. It was reported that the increase in SR concentration decreased the elastic modulus and increased the tensile strength of the blends. For blends with composition situated after phase inversion, the SR becomes the matrix, leading to a significant rise in the Vicat softening temperature and reduced thermal conductivity. Such improvements extend the range of applications of these materials as electrical insulators in environments with higher heat generation. 相似文献
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Processing, cure characteristics, and mechanical properties of EPDM rubber containing ground EPDM vulcanizate of known composition were studied. Mooney viscosity increases and Mooney scorch time decreases by the addition of the ground vulcanizate. At higher loadings of the ground rubber, the maximum rheometric torque decreases. On addition of ground waste, stress–strain properties and tear resistance increase, whereas heat buildup marginally increases, resilience marginally decreases, low‐strain modulus remains constant, and abrasion resistance decreases. The interplay between the filler effect of the ground EPDM and the crosslink density changes of the EPDM matrix is believed to be the reason for the variation in mechanical properties. It is believed that sulfur migration occurs from the raw EPDM matrix (R‐EPDM) to the ground waste EPDM (W‐EPDM) particle while accelerator migration occurs from W‐EPDM to R‐EPDM. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3293–3303, 2001 相似文献
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Xiting Wang Yansong Wang Lifeng Ma Hui Guo Chao Yang Ningning Liu Jincheng Wang 《Polymer Engineering and Science》2020,60(8):1877-1889
In this work, the ethylene-propylene-diene monomer (EPDM) foam was fabricated via 4-4′-oxobisbenzenesulfonyl hydrazide (OBSH) and phenolic resin (PF) in an effort to prepare the sound-absorbing composite which has excellent sound absorption at the medium and low frequency. For single-layer EPDM foams, cell morphology showed a certain pattern, causing the peak of the sound absorption coefficient move to a higher frequency and the peak value reached a maximum of about 0.75 as the OBSH content increased. In addition, with the foaming temperature increasing, the cell morphology had a different tendency and the peak of the sound absorption coefficient moved first to the higher frequency and then to the lower frequency due to the vulcanization reaction. Compared with the single-layer EPDM foams, the sound absorption curve of the double-layer composite made of the single-layer EPDM foam and pure EPDM sheet with cavities moved to a lower frequency by about 400 Hz. The theoretical calculation method was used to verify the accuracy of the experimental results. This work provided a simple approach to control the sound absorption property of EPDM foamed material and its double-layer composite through from an experimental and theoretical perspective. 相似文献
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Milena Ginic‐Markovic Namita Roy Choudhury Maria Dimopoulos Janis Matisons Chandima Kumudinie 《应用聚合物科学杂志》2001,80(14):2647-2661
The present investigation deals with studies on wettability, miscibility, and morphology of the macromolecularly modified EPDM. Two different maleated EPDM rubbers (grafted rubber) were chosen (0.5 and 1% maleation) for such modification and they were used in various proportions. Wettability of the rubber substrate, as observed from dynamic contact angle measurement, was improved using these grafted rubbers. Results of X‐ray photoelectron spectroscopy showed an increase in oxygen level with higher levels of grafted rubber in the blends. Morphology study by transmission electron microscopy showed a smaller domain size for the blend with higher maleic anhydride content in the grafted rubber. The viscosity versus blend ratio results showed a negative deviation behavior for blends with 1% grafted rubber, whereas a positive negative deviation behavior was observed in blends with 0.5% grafted EPDM. As the strength of interaction increased, the glass transition shifted to a higher temperature. All blends were heterogeneous, as indicated by different degrees of dispersion. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2647–2661, 2001 相似文献
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采用热空气自由发泡制备EPDM海绵,研究发泡剂品种和用量对其性能的影响。结果表明,以发泡剂AC、OBSH和H制备EPDM海绵,最佳用量分别为15、10和10份;当发泡剂用量为10份时,以发泡剂OBSH制备的EPDM海绵发泡倍率最大。 相似文献
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Starch microcellular foam was produced by supercritical fluid extrusion (SCFX) using native and pregelatinized starch mixtures. The starch solution was reacted with epichlorohydrin (EPI) under alkaline conditions in a continuous twin‐screw extruder in the presence of supercritical carbon dioxide. The relationship between crosslinking density and cell size and their distribution in the foamed extrudates was studied. An increase in the EPI concentration from 0 to 0.5% was accompanied by an increase in the degree of crosslinking as measured by differential scanning calorimetry and confirmed by diffusion coefficient measured by nuclear magnetic resonance. The diffusion coefficient of crosslinked sample was observed to be 12.5 times lower than that of non crosslinked control. The average cell size of the microporous structure, observed by scanning electron microscopy, showed a decrease from 147 to 61 μm as the concentration of EPI was increased. The cell size distribution of the crosslinked samples was significantly improved but the total expansion was lowered. The results obtained to date indicate, for the first time, that reactive extrusion of starch with EPI with supercritical carbon dioxide as a blowing agent offers a promising new technique to generate microporous foams for use in various applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献