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1.
PVC/环氧化天然橡胶共混型热塑性弹性体的制备   总被引:4,自引:2,他引:2       下载免费PDF全文
应用动态硫化技术.试验了共混温度、PVC母料与环氧化天然橡胶(ENR)母炼胶的混合时间、动态硫化时间、共混方式以及ENR母炼胶门尼粘度等工艺因素对PVC/ENR共混型热塑性弹性体性能的影响。结果表明,当共混温度在160-170℃、混合时间为3min、ENR母炼胶门尼粘度ML(1+4)100℃=18时.采用一段共混方式可制得性能较好的热塑性硫化胶。通过Brabender塑性仪,对PVC/ENR共混物在密炼室中的动态硫化全过程进行了分析。  相似文献   

2.
PVC/ENR/XNBR(NBR)动态硫化共混物   总被引:1,自引:0,他引:1  
能干不氧化天然橡胶(ENR)、聚氯乙烯(PVC)和羧基丁腈橡胶(XNBR)之间的自硫化反应,实现了PVC/ENR/XNBR三元共混物的动态友化,由此得到了具有热塑性弹性体的一些典型特征的PVC/ENR/XNBR动态自硫化共混物。该人混物与自硫化反应不明显的PVC/ENR/NBR共混物进行了比较,发现动态自硫化反应显著提高了共混物的综合性能。结果表明,当橡塑比为70/30时,前者的拉伸强度为11.8  相似文献   

3.
ENR/CSM的自硫化研究   总被引:3,自引:0,他引:3  
研究在没有任何硫化剂的情况下环氧化天然橡胶(ENR-50)和氯磺化聚乙烯(CSM-40)共混物的自硫化,以及共混比、填料品种及用量、间苯撑双马来酰亚胺与马来酸酐等活性剂、硫化温度和时间对交联程度和性能的影响。结果表明ENR/CSM共混体可以产生自硫化;共混比为50/50时交联密度最大,性能最佳,炭黑和白炭黑对该体系有好的补强作用,但白炭黑的补强作用比炭黑的好;间苯撑双马来酰亚胺及马来酸酐能活化自硫化体系;延长硫化时间及提高硫化温度均可增加交联作用,该自硫化体系没有返原现象。  相似文献   

4.
重点研究环氧化天然橡胶(ENR)的环氧化程度,PVC/ENR配比,硫化体系(交联剂及共交联剂),填充补强体系以及增塑剂对PVC/ENR共混型热塑性弹性体物理性能的影响。结果表明当ENR的环氧化程度为50mol%,PVC/ENR=50/50,采用DCP作交联剂,硫黄作共交联剂,在ENR中充入适量的重质芳烃油,通过适宜的工艺条件和动态硫化方式,可制出力学性能较好的PVC/ENR共混型TPV。  相似文献   

5.
GMA熔融接枝EPDM/NR共混物的动态硫化   总被引:3,自引:2,他引:1       下载免费PDF全文
研究了甲基丙烯酸缩水甘油酯(GMA)熔融接枝EPDM(EPDMgGMA)与NR共混物的动态硫化。考察了GMA用量、交联剂品种和用量以及动态硫化工艺条件对EPDMgGMA/NR动态硫化共混物力学性能的影响。结果表明:与直接静态硫化物相比,动态硫化物的拉伸强度提高了482%,热氧老化性能也得到了明显的改善;GMA用量为3~5份、二乙烯三胺(DETA)用量为03份时,动态硫化共混物的力学性能较好;动态硫化的工艺条件对共混物性能无明显影响。另外,红外光谱测试表明,EPDM确实成功接枝了GMA。  相似文献   

6.
NR/NBR/氯醚橡胶三元共混物性能的研究   总被引:1,自引:1,他引:0       下载免费PDF全文
罗利玲  谭晓明  刘承美 《橡胶工业》1998,45(10):579-582
采用双硫化体系,制备了NR/NBR/氯醚橡胶(CO)三元共混硫化胶,并对硫化胶的性能进行了测试。实验结果表明:采用促进剂NA22/硫黄/氧化锌硫化体系可实现共混物的同步硫化;CO对NR的性能有较大的影响,少量的CO可有效地提高NR的耐老化、耐介质和气密性,但共混物的耐水性能比NR略有下降。  相似文献   

7.
平衡硫化体系硫化天然橡胶的性能研究   总被引:7,自引:3,他引:4       下载免费PDF全文
对平衡硫化(EC)体系硫化天然橡胶(NR)的性能进行了研究,并与半有效硫化(SEV)体系和传统硫化(CV)体系硫化NR进行了对比。结果表明,EC体系返原作用略高于SEV体系,明显低于CV体系,硫化6h时的返原率依次为7.7%,0.4%和34.0%;与SEV和CV体系相比,EC体系NR硫化胶拉伸强度、撕裂强度和300%定伸应力高,生热低,耐磨性和耐屈挠性好。EC体系NR硫化胶的耐热氧老化性能优于SEV体系,更优于CV体系。  相似文献   

8.
氯化丁基橡胶/天然橡胶共混物性能的研究   总被引:3,自引:1,他引:2       下载免费PDF全文
研究了共混比及硫化体系对氯化丁基橡胶(CIIR)/天然橡胶(NR)共混物性能的影响,探讨了老化温度及防老剂对氧化锌/促进剂TMTD/促进剂DM硫化体系硫化的CIIR/NR共捐物耐热氧老化性能的影响。试验结果表明,氧化锌/促进剂TMTD/促进剂DM(5.0/1.5/1.0)硫化体系硫化的CIIR/NR共混物的拉伸强度和扯断伸长率与按共混比计算的平均值差别较小,尤其是拉伸强度与计算值完全一致。当共混物中CIIR用量超过50份时,共混物的耐热氧老化性能明显改善。不同防老剂对CIIR/NR(50/50)共混物热氧老化的防护效能大小顺序为RD及4010>4010NA>MB>D。防老剂RD先加入到NR中后再与CIIR共混.其防护效能更佳。  相似文献   

9.
锡偶联型溶聚丁苯橡胶/天然橡胶共混物的性能   总被引:2,自引:0,他引:2  
研究了不同共混比的锡偶联型溶聚丁苯橡胶/天然橡胶(SSBR/NR)共混物的生胶及硫化胶的性能及断裂形态。实验表明,SSBR/NR共混物具有单一的玻璃化转变温度、共混体系为相容体系。SSBR与NR共混后,改善了SSBR的加工性能,提高其拉伸细度和撕裂强度。当SSBR/NR(质量比)为80/20时,共混物的硫化胶具有最优的力学性能。  相似文献   

10.
研究了稀土顺丁橡胶(Ln-BR)与天然橡胶(NR)以不同比例共混后生胶、混炼胶和硫化胶的性能,并与相同条件下的镍系顺丁橡胶(Ni-BR)/NR共混胶的性能进行了对比,结果表明,共混胶随Ln-BR用量的增大,ML^100℃1+4降低,工艺行为良好,硫化胶力学性能、磨耗、湿滑指数和生热值下降,并且Ln-BR/NR硫化胶的抗湿滑性和动态疲劳性均优于Ni-BR/NR硫化胶。  相似文献   

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Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.  相似文献   

13.
In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.  相似文献   

14.
Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.  相似文献   

15.
Glycidyl carbamate chemistry combines the excellent properties of polyurethanes with the crosslinking chemistry of epoxy resins. Glycidyl carbamate functional oligomers were synthesized by the reaction of polyfunctional isocyanate oligomers and glycidol. The oligomers were formulated into coatings with several amine functional crosslinkers at varying stoichiometric ratios and cured at different temperatures. Properties such as solvent resistance, hardness, and impact resistance were dependent on the composition and cure conditions. Most coatings had an excellent combination of properties. Studies were carried out to determine the kinetics of the curing reaction of the glycidyl carbamate functional oligomers with multifunctional and model amines. Detailed kinetic analysis of the curing reactions was also undertaken. The results indicated that the glycidyl carbamate functional group is more reactive than a glycidyl ether group. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, on October 27–29, 2004, in Chicago, IL.  相似文献   

16.
A highly moisture-proof polysilsesquioxane coating was obtained from a new bis-silylated precursor, which was synthesized from 3-aminopropyltriethoxysilane (APTES) and m-xylylene diisocyanate (m-XDI) in tetrahydrofuran (THF) and verified by 1H MAS NMR. For direct comparison purposes, an SiO2 coating was also prepared by the Stöber method using tetraethoxysilane (TEOS) as the reactant. Interestingly, the coating obtained from the polysilsesquioxane sol exhibited a much higher moisture resistance capability than its counterpart, which was attributed to its more compact feature between nanoparticles as characterized by N2 absorption experiment and transmission electron microscopy (TEM). Furthermore, its high transparency of about 92% showed potential for application in the protection of optical crystals.  相似文献   

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