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1.
为了改善废轮胎胶粉(GRT)增韧废PP复合材料的力学性,用橡胶再生剂De-link对废胶粉进行改性再生.结果表明,加入3份再生剂De-link,可使废PP/GRT复合材料的冲击强度和拉伸强度有很大的提高;复合材料的冲击断面扫描电镜分析显示,经再生剂改性后复合材料的分散相尺寸明显减小,相容性显著提高.  相似文献   

2.
为了改善废轮胎胶粉(GRT)增韧废PP复合材料的力学性能,用橡胶再生剂De-link对废胶粉进行改性再生。结果表明,加入3份再生剂De-link,可使废PP/GRT复合材料的冲击强度和拉伸强度有很大的提高;复合材料的冲击断面扫描电镜分析显示,经再生剂改性后复合材料的分散相尺寸明显减小,相容性显提高。  相似文献   

3.
马来酸酐接枝胶粉对胶粉/HDPE共混材料影响的研究   总被引:2,自引:1,他引:1  
探讨了胶粉(GRT)和高密度聚乙烯(HDPE)共混时胶粉的粒径、相容剂以及马来酸酐接枝胶粉(GRT-g-MAH)的用量对GRT/HDPE共混物力学性能的影响.用热分析以及扫描电子显微镜对共混材料的热行为以及形貌进行了分析.结果表明:制备GRT/HDPE复合材料时,胶粉的粒径越小,所得材料的拉伸性能越好,添加相容剂可进一步改善共混材料的性能.在体系中添加(;RT-g-MAH时,共混物的力学强度也能得到提高,且GRT-g-MAH的加入量为17%时,共混物的力学强度达到最高,表明GRT-g-MAH可用作胶粉/HDPE共混的相容剂.  相似文献   

4.
废胶粉填充改性RHDPE增容研究   总被引:2,自引:0,他引:2  
研究了废胶粉的活化处理、不同种类相容剂对回收高密度聚乙烯/废胶粉(RHDPE/WRP)共混体系的增容效果.结果表明,WRP活化处理对提高WRP界面活性有效果.不同相容剂对提升共混体系性能的影响不同,其中添加10份马来酸酐接枝聚乙烯(PE-g-MAH)相容剂对提升RHDPE/活化WRP体系整体性能最有效,可使RHDPE/WRP共混材料的拉伸强度从简单共混物的18.8 MPa提高到22.5 MPa,缺口冲击强度从37.5 kJ/m2提高到60.9 kJ/m2;热变形温度从55.8℃提高到63.6℃.  相似文献   

5.
改性胶粉在废旧苯乙烯类混杂塑料中的应用研究   总被引:7,自引:0,他引:7  
董智贤  周彦豪  贾德民 《塑料》2005,34(1):52-55
研究了采用不同方法对精细胶粉(GRT)进行改性,并应用于废旧苯乙烯类混杂塑料(WPS)中,详细讨论了改性精细胶粉的用量对于复合材料体系拉伸强度、冲击强度等力学性能的影响。测试结果表明,对于不同改性方法制备的改性胶粉,均是在WPS中用量为5份时,所得复合材料的综合性能较好。其中,De link再生剂与SBR并用改性胶粉与WPS复合材料的拉伸强度为最高,为基体WPS的88 2%,较之未改性WPS/GRT提高了51 5%;羧基丁苯胶乳、引发剂BPO和偶联剂A 174并用改性胶粉/废旧苯乙烯类混杂塑料的冲击强度最高,比废塑料基体提高了43 3%,比未改性GRT/WPS复合材料提高了2 5倍。扫描电镜测试分析表明,胶粉改性可有效改善其与塑料基体间的界面粘合。  相似文献   

6.
采用熔融挤出共混的方法,选用三种废胶粉填充聚丙烯(PP),制备了PP/废胶粉复合材料,研究了废胶粉质量分数对复合材料力学性能的影响.结果表明:废旧三元乙丙橡胶粉可明显提高复合材料冲击强度和拉伸断裂应变,当其质量分数为60%时,简支梁缺口冲击强度可提高33%,拉伸断裂应变增大了26%,有显著的增韧效果:废旧杂胶粉的加入使...  相似文献   

7.
制备聚丙烯(PP)/乙烯-醋酸乙烯共聚物(EVA)/胶粉热塑性弹性体(TPV),研究胶粉改性剂201酚醛树脂、松香、橡胶活化剂450、橡胶再生剂RV,相容剂聚丙烯接枝马来酸酐(PP-g-MAH)用量,以及EVA/胶粉共混比对TPV性能的影响。结果表明:与采用未改性胶粉相比,采用改性胶粉制得的TPV拉伸强度、拉断伸长率和撕裂强度增大;当PP-g-MAH用量为5份、EVA/胶粉共混比为15/45时,TPV的综合性能较好。  相似文献   

8.
胶粉/LLDPE弹性体合金的研制   总被引:3,自引:0,他引:3  
系统研究了废胶粉(GRT)/线型低密度聚乙烯(LLDPE)弹性体合金(GRT/LLDPE)的配方,以及粒径,GRT含量,相容剂和硫化剂(DCP)用量对共混物力学性能的影响,结果表明,采用两阶共混法,当GRT/LLDPE共混比为:60:40,DCP用量为2份,相容剂马来酸酐三单体接枝物用量为3-5份时,所得弹性体合金力学性能最佳,弹性体合金的拉伸强度从简单共混物的5.8Mpa上升到11.1MPa,撕裂强度从39.4kN/m,上升到63.4kN/m,断裂伸长率从180%增加到260%。  相似文献   

9.
采用熔融共混制备了不同相容剂马来酸酐接枝聚丙烯(PP-g-MAH)含量的聚丙烯(PP)/PP-g-MAH/聚酰胺12(PA12)共混体系,通过对体系的平衡扭矩、差式扫描量热法(DSC)、扫描电子显微镜(SEM)及力学性能等测试,分析了共混体系中相容剂PP-g-MAH对PP/PAl2形貌及性能的影响.结果表明,PP-g-MAH能改善PP/PAl2的界面相容性,PA12能更好地分散在PP基体中,最佳相容剂添加质量分数为12%.此时,杨氏模量比未添加相容剂时提高了60.7%,断裂伸长率提高了79.9%,冲击强度提高了345.2%.  相似文献   

10.
采用熔融挤出的方法制备聚丙烯(PP)、冷冻胶粉(LGTR)、相容剂及增韧剂的共混物,研究了胶粉用量、相容剂种类和用量及增韧剂对共混体系力学性能和微观结构的影响。结果表明,LGTR的加入会降低PP的力学性能,但随着LGTR用量的增加,共混体系的冲击强度上升;相容剂的使用会增加PP与LGTR的相容性,使力学性能提高;热塑性聚烯烃类弹性体(POE)和三元乙丙胶接枝马来酸酐(EPDM-g-MAH)的使用可以有效提高PP/胶粉共混体系的缺口冲击强度,并且增韧剂的使用可以提高PP与LGTR之间的相容性;高密度聚乙烯(PE-HD)/POE并用做增韧体系时,可以进一步提升共混体系的韧性,提高冲击强度。  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.
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   

14.
It is well established that a wide range of drugs of abuse acutely boost the signaling of the sympathetic nervous system and the hypothalamic–pituitary–adrenal (HPA) axis, where norepinephrine and epinephrine are major output molecules. This stimulatory effect is accompanied by such symptoms as elevated heart rate and blood pressure, more rapid breathing, increased body temperature and sweating, and pupillary dilation, as well as the intoxicating or euphoric subjective properties of the drug. While many drugs of abuse are thought to achieve their intoxicating effects by modulating the monoaminergic neurotransmitter systems (i.e., serotonin, norepinephrine, dopamine) by binding to these receptors or otherwise affecting their synaptic signaling, this paper puts forth the hypothesis that many of these drugs are actually acutely converted to catecholamines (dopamine, norepinephrine, epinephrine) in vivo, in addition to transformation to their known metabolites. In this manner, a range of stimulants, opioids, and psychedelics (as well as alcohol) may partially achieve their intoxicating properties, as well as side effects, due to this putative transformation to catecholamines. If this hypothesis is correct, it would alter our understanding of the basic biosynthetic pathways for generating these important signaling molecules, while also modifying our view of the neural substrates underlying substance abuse and dependence, including psychological stress-induced relapse. Importantly, there is a direct way to test the overarching hypothesis: administer (either centrally or peripherally) stable isotope versions of these drugs to model organisms such as rodents (or even to humans) and then use liquid chromatography-mass spectrometry to determine if the labeled drug is converted to labeled catecholamines in brain, blood plasma, or urine samples.  相似文献   

15.
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   

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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   

19.
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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