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1.
宋赫  邓新华  孙元 《中国塑料》2012,26(2):37-40
用端胺基非异氰酸酯基聚氨酯预聚体与聚醚型聚氨酯预聚体嵌段共聚制备了改性聚醚型聚氨酯及其膜,分析了端胺基非异氰酸酯基聚氨酯预聚体,考查了聚醚型聚氨脂树脂成膜温度和预聚体NCO/ NH2配比对膜力学性能的影响,同时对比了聚氨酯材料的力学性能,采用差示扫描量热法(DSC)研究了相分离程度。结果表明,合成的端胺基非异氰酸酯基聚氨酯预聚体中成功地引入了氨基甲酸酯基团;最佳成膜温度为140 ℃;当预聚体NCO/NH2=1/0.9(摩尔比,下同)时膜的性能最好,拉伸强度为25.1 MPa,伸长100 %模量为5 MPa,;与普通聚氨酯相比,端胺基非异氰酸酯基聚氨酯预聚体嵌段的聚氨酯力学性能更高;DSC曲线显示其有2个不同的玻璃化转变温度,相分离明显。  相似文献   

2.
以聚醚二元醇、二异氰酸酯为主要原料合成了硅烷封端聚氨酯预聚体,使用合成得到的预聚体制备了硅烷封端聚氨酯密封胶并对其性能进行了考察。研究了二异氰酸酯类型,NCO/OH比例,反应温度,扩链剂类型及封端剂类型对硅烷封端聚氨酯(SPU)的影响。结果表明:使用两种混合二异氰酸酯,NCO∶OH=1.3~1.5,二甘醇作为扩链剂,γ-巯丙基三甲基硅烷(KH590)作为封端剂,反应温度85℃制备得到较理想的预聚体,可使硅烷封端聚氨酯密封胶拉伸强度达到1.78MPa,断裂伸长率达到490%。  相似文献   

3.
甘厚磊  易长海  金雪  曹菊胜 《粘接》2008,29(2):11-13
采用蓖麻油、甘油、TDI等为原料,合成出端-NCO的蓖麻油基聚氨酯PU预聚体.对预聚体中NCO的含量进行了测定,采用FT-IR对材料进行了定性分析,对树脂的固化工艺进行了探讨.结果表明,蓖麻油基PU预聚体的NCO质量分数在4.93%~5.25%时,树脂在-18~40 ℃能固化成膜,表干时间<1 h.  相似文献   

4.
蓖麻油聚氨酯防水涂料的制备与性能研究   总被引:2,自引:0,他引:2  
采用可再生的蓖麻油先分别与三羟甲基丙烷(TMP)、甘油反应,再与TDI反应,生成端基为-NCO的蓖麻油基聚氨酯预聚体.对其-NCO含量进行测试,并采用FT-IR对材料进行定性分析.并对固化后的涂膜附着力、力学性能、耐磨性和耐水性能进行了测试.结果表明:采用甘油醇解蓖麻油合成的聚氨酯性能较好,其最佳反应时间为3~4 h,反应后-NCO含量为4.90%~5.32%,体系在-10~40℃能固化成膜,且成膜物有较好的防水性能和力学性能.  相似文献   

5.
西安工程大学的张鹏等人以2,4-甲苯二异氰酸酯与聚乙二醇为原料,经预聚反应得到聚氨酯预聚体;再用γ-氨丙基三乙氧基硅烷封端改性,得到有机硅改性水性聚氨酯。当γ-氨丙基三乙氧基硅烷的用量为预聚体质量的5%时,改性聚氨酯的成膜性显著提高,膜的吸水性为17.2%。  相似文献   

6.
噁唑烷潜固化剂改性聚氨酯预聚体性能研究   总被引:1,自引:0,他引:1  
以改性二苯基甲烷二异氰酸脂和聚醚多元醇等为原料,合成了噁唑烷潜固化剂改性聚氨酯预聚体,讨论了预聚体的异氰酸酯基含量及噁唑烷潜固化剂用量对固化性能的影响。结果表明,通过傅立叶变换红外光谱(FT-IR)对预聚体成膜的固化动态进行了分析表征,当NCO基质量分数为2.3%、噁唑烷潜固化剂质量分数为2.5%~3.5%时,预聚体固化时不产生发泡膨胀;固化20h后反应完全。  相似文献   

7.
利用3-异氰酸酯基丙基三甲氧基硅烷(KH901)与聚氧化丙烯二醇(PPG)端羟基的封端反应,合成了可湿气固化硅烷封端聚氨酯(STPU)。探讨了硬段含量、PPG分子量与树脂黏度、胶膜硬度和力学性能之间的关系,建立了STPU封端效率的表征方法。结果表明:提高PPG分子量会降低封端效率,增加树脂黏度,提高固化后胶膜的断裂伸长率;将过量PPG8000与异佛尔酮二异氰酸酯(IPDI)预聚,再与KH901反应,可制备高分子量STPU,但分子量分布较宽,黏度较大,固化后胶膜的断裂伸长率为140%;通过高分子量PPG18000与KH901的直接反应封端,合成的STPU黏度适中,胶膜断裂伸长率达240%,且合成步骤简单。  相似文献   

8.
硅烷改性聚氨酯的合成研究   总被引:1,自引:0,他引:1  
以氢基硅烷偶联剂为基础,对以异氰酸酯基为端基的聚氨酯预聚体进行再封端.合成了一系列不同硅烷封端率的单组分温固化聚氨酯。测试结果表明:硅烷偶联剂成功接枝在聚氨酯预聚体上.产物的表干时间、粘接强度、耐湿热都得到很大改善,力学强度在一定封段率下保持较好.在聚氨酯密封胶、弹性体等领域有很好的应用前景。  相似文献   

9.
以3种硅烷偶联剂对湿固化聚氨酯热熔胶分别进行改性,制备了硅烷改性的湿固化聚氨酯(SPU)热熔胶,用热重分析、熔融黏度和粘接测试等方法对所合成材料进行表征。结果表明,采用KH550与异氰酸酯基的摩尔比值0.15进行改性,所制备的SPU热熔胶综合性能最佳,剪切强度比未改性的胶增加41.5%,固化物具有较好的热稳定性。  相似文献   

10.
以3-异氰酸酯基丙基三乙氧基硅烷(IPTS)和聚醚多元醇(PPG)为主要原料,以二月桂酸二丁锡为催化剂,合成端硅烷改性聚氨酯预聚体,并在预聚体中添加贮存稳定剂A-171和催化剂辛酸亚锡制备单组分湿固化密封胶用端硅烷改性聚氨酯树脂。研究表明,相对于进口同类产品,该树脂黏度低,在18000 m Pa·s以下,具有优良的力学性能。  相似文献   

11.
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   

12.
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   

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Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.  相似文献   

18.
收集了2007年7月~2008年6月世界塑料工业的相关资料,介绍了2007~2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.  相似文献   

19.
收集了2005年7月~2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、通用热固性树脂(酚醛、聚氨酯、不饱和树脂、环氧树脂)、特种工程塑料(聚苯硫醚、液晶聚合物、聚醚醚酮)的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。  相似文献   

20.
Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.  相似文献   

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