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1.
羟乙基纤维素添加在醋丙乳液中做保护胶体的初步研究   总被引:1,自引:0,他引:1  
采用羟乙基纤维素为保护胶体制备了醋丙乳液,探讨了乳液聚合过程中共聚单体配比、保护胶体用量、温度和引发剂等因素对乳液聚合的影响,多方面考察乳液的性能.结果表明:羟乙基纤维素为保护胶体可制备稳定的醋丙乳液,该乳液具有优良的电解质性能.  相似文献   

2.
以纤维素粉(α-Cellulose)为原料,通过酸水解法制备得到纳米纤维素(CNC),并对其结构和微观形貌进行了表征。选用大豆油为油相,羟乙基纤维素(HEC)/CNC复合物为乳化剂,制备得到稳定的Pickering乳液。研究CNC质量分数、油水体积比和HEC质量分数对Pickering乳液稳定性的影响,并通过流变学的手段对其进行分析。结果表明,随着HEC质量分数的增加,Pickering乳液稳定性增强。在油水体积比为8∶2,CNC质量分数为0.2%和HEC质量分数为0.4%时,乳液稳定性最强,其乳滴粒径约为20μm,稳定时长可达100天以上。与单独使用CNC稳定的Pickering乳液相比,HEC/CNC复合物稳定的Pickering乳液具有更强的稳定性和更小的液滴直径。HEC/CNC复合物稳定的Pickering乳液呈现“剪切变稀”的流变特性,即溶液中HEC质量分数增加时,乳液剪切黏度随着剪切速率的增大而降低,剪切应力则相应地增强。  相似文献   

3.
以改性聚硅氧烷为主要成膜物,丙烯酸酯共聚乳液为辅助成膜物,加入无机阳离子抗菌助剂,制备了具有抗菌抗病毒功能的内墙陶瓷涂料.分别研究了丙烯酸酯共聚乳液与改性硅氧烷的不同配比对涂料综合性能的影响,通过加入羟乙基纤维素调整涂料的施工性,并用ATP荧光检测仪初步测试了涂料的抗菌性和抗菌持久性.  相似文献   

4.
高固体分无凝胶丙烯酸酯乳液合成工艺探讨   总被引:1,自引:0,他引:1  
为制备高固体分无凝胶丙烯酸酯乳液,探讨了聚合方法,单体和引发剂的加料方式,乳化剂用量和种类,以及保护胶体种类对丙烯酸酯乳液性能的影响。结果表明:全部预乳化效果最佳,4h内无凝胶产生;半连续滴加较一次性或分批加入更有利于乳液体系稳定;采用阴离子与非离子乳化剂复配及加入保护胶体有利于提高聚合体系的固含量。筛选出最佳的制备工艺条件:采用全部预乳化、半连续种子乳液聚合;以十二烷基硫酸钠(SDS)与烷基酚聚氧乙烯醚(OP-10)为复合乳化剂(质量比为1:1),其用量为3%;保护胶体量为0.8%;引发剂量为0.3%;反应温度为78℃;反应时间为4h;搅拌速率为400r/min。此条件下可合成固含量达60.03%的带蓝光乳白色丙烯酸酯乳液。  相似文献   

5.
缔合增稠剂是具有表面活性的聚合物。常用的是聚乙二醇醚的两端以,酯键各连接一个烷链,称之为亲油改性乙氧基化氨酯(HEUR)。它对乳胶漆的增稠机理与非缔合增稠剂不同。后者是以增大液体动力体积来使水相增稠的,而缔合增稠剂是通过自聚集以及与表面活性剂组成?昆合胶束,颗粒和颜料颗粒上亲油点缔合而使体系增稠的。这些聚集和缔合而形成的结构在剪切下会解开,在剪切力消失后又重新聚集和缔合,恢复了触变性,这是单靠液体动力体积增稠的非缔合增稠剂所没有的。图1是乳胶漆分别用羟乙基纤维素和HEUR调节到90KU后的粘度曲线。从图1中可见:用HEUR增稠的乳胶漆,在高剪切速率下比羟乙基纤维素增稠的有较高的粘度,这将有利于厚涂来补偿干燥后遮盖力的下降;在低剪切速率下有较低的粘度,这将有利于流平。  相似文献   

6.
黄洪  林劲冬  陈焕钦 《涂料工业》2007,37(3):22-26,29
以分子链一端为巯基的聚乙烯醇(PVA-SH)为保护胶体,合成了空间稳定的硅氧烷改性丙烯酸酯聚合物乳液。在微碱性乳液聚合条件下,成功制备出异丙氧基硅烷含量高达11.2%(质量分数)的硅丙聚合物。经傅里叶变换红外光谱测定证明,在种子乳液聚合阶段,PVA-SH与MMA单体发生了接枝反应,形成具有PVA-S-PMMA结构的线型两亲接枝聚合物。TEM观察显示,所得到的乳胶粒大小均匀并且PVA-SH对其包覆均匀完整。凝胶渗透色谱(GPC)的测试结果表明,PVA-SH和(或)PVA-S-PMMA稳定的硅氧烷改性丙烯酸酯聚合物的数均相对分子质量(Mn)可以控制在60000-70000之间。在水解性能十分稳定的异丙氧基硅烷改性丙烯酸酯聚合物乳液的成膜过程中,可以通过调节pH值到微酸性,催化硅氧烷基团的水解反应,提高聚合物膜的交联速率和密度。PVA-SH稳定的异丙氧基硅烷改性P(MMA-BA)共聚物乳液能够经受24000r/min(约62m/s)的高速剪切作用而保持粒径的稳定性。这种聚合物乳液能获得性能良好的涂膜,是潜在的新型建筑涂料的成膜物质。  相似文献   

7.
高炜斌 《化学工程师》2006,20(10):12-14
本文尝试用聚丙烯酰胺、羧甲基纤维素及乙基纤维素代替聚乙烯醇作醋酸乙烯乳液聚合的保护胶体。实验结果显示,聚丙烯酰胺、乙基纤维素可以作为醋酸乙烯乳液聚合的保护胶体。本文对所得乳液的物化性质尚未进行详细研究。  相似文献   

8.
介绍醋酸乙烯-乙烯-丙烯酸酯多元共聚乳液的研究情况。在高压反应釜中采用间歇聚合工艺进行乳液聚合,使用聚乙烯醇作为主要保护胶体,并配合适宜的非离子和阴离子乳化剂,采用氧化-还原引发体系,通过引入丙烯酸酯类软单体,实现乙烯-醋酸乙烯-丙烯酸酯多元共聚,生产出低温柔性好、对非极性材料(例如BOPP)具有优异粘接强度的新型醋酸乙烯-乙烯乳液。用于防水涂料和包装行业,效果优良。  相似文献   

9.
环氧丙烯酸酯改性光固化水性聚氨酯的合成及性能研究   总被引:2,自引:1,他引:2  
采用环氧丙烯酸酯(PPG-EA)、甲苯-2,4-二异氰酸酯(TDI)、聚丙二醇(PPG)、二羟甲基丙酸(DM-PA)和丙烯酸羟乙酯(HEA)等制备了环氧丙烯酸酯改性光固化水性聚氨酯乳液(WPU);研究了改性环氧丙烯酸酯用量、DMPA用量、n(—NCO)∶n(—OH)对乳液及涂膜性能的影响。结果表明:通过环氧丙烯酸酯改性的水性聚氨酯涂膜具有硬度高、耐水性和力学性能好的特点,并且克服了环氧树脂直接用于水性聚氨酯改性制备的乳液贮存稳定性差的不足。当改性环氧丙烯酸酯用量为6%-10%、DMPA用量为5.5%-7.5%、n(—NCO)∶n(—OH)为1.3-1.4时,UV固化水性聚氨酯乳液的综合性能较好。  相似文献   

10.
羧甲基纤维素(CMC)的多环、多羟基结构有良好的油水选择性、耐温性和反应活性,适合与高价金属离子进行羟桥络合反应制备冻胶型堵水剂。作者对CMC铬冻胶耐温性、耐酸碱性、耐盐性及抗剪切性进行考察。实验结果表明与聚丙烯酰胺(HPAM)铬冻胶相比,CMC铬冻胶耐温性提高约40℃,可承受140℃高温;在pH=6-10、矿化度低于9000mg/L时,胶体强度较大,稳定性良好;胶体在剪切速率为2-100s-1时,冻胶粘度始终高于1000mPa·s,明显优于HPAM铬冻胶,可用于双液法堵水。  相似文献   

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12.
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   

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14.
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   

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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   

18.
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   

19.
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   

20.
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   

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