共查询到19条相似文献,搜索用时 187 毫秒
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室温自交联丙烯酸乳液与硅溶胶共混研究 总被引:5,自引:0,他引:5
将室温自交联丙烯酸乳液与硅溶胶双组分共混,并对共混乳液以及放置两天后的共混乳液的流变性能作了研究,发现:乳液的表观黏度(ηa)、稠度系数K、零剪切黏度(η0)均随硅溶胶含量的增加而增大,而乳液的假塑性增强;并且放置两天后的共混乳液的ηa、K、η0进一步增大,假塑性也增强。用IR、DSC对共混后的乳胶膜进行表征和测试,发现共混后的乳胶膜的硬度、耐水性、交联度、抗冲击强度、玻璃化转变温度均有提高,且附着力良好。 相似文献
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水性室温自交联聚丙烯酸酯乳液的制备及性能 总被引:1,自引:0,他引:1
以双丙酮丙烯酰胺(DAAM)、甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)和丙烯酸(AA)为共聚单体,采用预乳化和半连续种子乳液聚合工艺合成了水性室温自交联聚丙烯酸酯乳液(AACPA)。作为对比,合成了相应的常规聚丙烯酸酯乳液(CPA)。对两种乳液的粒径大小及分布、形态结构,两种乳胶膜的玻璃化转变温度(Tg)及力学性能等进行了系统的研究和对比。红外光谱(FT-IR)分析表明,室温下交联剂与功能单体双丙酮丙烯酰胺发生了交联反应;透射电镜(TEM)和动态激光光散射(DLS)表明,两种乳胶粒子均呈球状,但AACPA乳胶粒子的粒径更小,分布更窄。此外,相比于未交联的CPA膜,AACPA乳胶膜具有更高的Tg及更优异的力学性能。 相似文献
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采用单体直接滴加-半连续乳液聚合工艺合成了二十二烷基聚氧乙烯醚甲基丙烯酸酯(BEM)含量不同的疏水改性碱溶性聚丙烯酸乳液(HASE)。控制NaOH/COOH的摩尔比(R),研究了R对HASE体系的pH、透光率、黏度、溶解参数(SP)、表观离解常数(p Ka)及η_0、η_∞、[η]和流变性的影响。结果表明,pH在R=0.1~0.8范围呈平台状,HASE相态转变的起点是R≈0.4,终点是R≈0.8,对应的pH≈7;BEM量越多,质子迁移吉布斯能(ΔGel)越大,相态转变的R值越高;η0、η∞曲线在R≈0.8前后表现出2个斜率,而[η]只有1个斜率,且η0、η∞、[η]具有p H敏感性;稠度系数(K)随pH和BEM增加先增后降,流动指数(n)随p H和BEM先减小后增大。 相似文献
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针对大庆油田应用的两亲聚合物,通过扫描电镜揭示了其微观结构;利用MCR301流变仪测定了两亲聚合物的流变性,使用Carreau模型对流变曲线进行了拟合,确定了Na+、K+、S2-浓度越高,体系的黏度越低,η0越小;Ca2+、Mg2+浓度增加,η0先增加后降低。同时,研究了温度对两亲聚合物溶液黏度的影响,浓度低于临界聚集浓度(CAC)值时,浓度越高,两亲聚合物溶液的黏度对温度越敏感,而浓度高于CAC值后的规律则相反。因此,对于两亲聚合物驱,应选择浓度尽可能高于CAC值的体系。 相似文献
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聚合工艺对核壳型丙烯酸酯乳液性能的影响 总被引:1,自引:0,他引:1
采用间歇法、半连续滴加法和预乳化半连续滴加法等种子乳液聚合工艺,制备了核壳型丙烯酸酯乳液,研究了聚合工艺对乳液性能以及漆膜力学性能的影响,并用激光纳米粒度仪和透射电镜(TEM)对乳胶粒子进行了表征。结果表明,当丙烯酸质量分数为4%,核、壳层中甲基丙烯酸甲酯与丙烯酸丁酯的质量比分别为3∶7和7∶3,核壳总单体质量比为1∶1,核层和壳层反应温度分别为70℃和80℃时,采用预乳化半连续滴加法可以合成黏度适中、乳胶粒径小且分布均匀、稳定性好和漆膜力学性能优良的核壳型丙烯酸酯乳液。 相似文献
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高固含量丙烯酸酯共聚物乳液的单体组成与流变行为 总被引:3,自引:0,他引:3
合成了一系列固体含量为70%的丙烯酸丁酯/甲基丙烯酸甲酯/α-甲基丙烯酸(BA/MMA/MAA)共聚物乳液,研究了软(BA)、硬(MMA)段单体用量比对乳液体系流变行为的影响,并对其乳胶粒的粒径分布和微观形态进行了表征。结果表明,所合成乳液乳胶粒的粒径在50nm~650nm范围内,呈宽分散分布状态。当BA/MMA<60/40时,乳液可保持低黏度;而当BA/MMA>60/40时,乳液的黏度急剧增加。随着乳液中软、硬段单体比的不同,乳液的乳胶粒分布状态和凝聚形态均有显著变化。 相似文献
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通过2,4-甲苯二异氰酸酯(TDI)、2,2-二羟甲基丁酸(DMBA)、聚乙二醇(PEG)和环氧树脂(e-44)反应合成了一种新型的环氧基多支链反应型乳化剂,该乳化剂表现出优异的乳化性能。因其环氧值约为0.1mol/100g,可以作为自乳化环氧树脂应用。通过红外光谱分析和盐酸-丙酮滴定法研究反应历程,采用不同分子量的聚乙二醇来探究聚乙二醇分子量对乳化剂性能的影响。研究表明,乳化剂的C.P点、HLB值和CMCs随着聚氧化乙烯链段的增加而升高,Γ值减小,S-3乳化剂性能最佳。乳液性能研究表明,当e-44/S-3为20/100时,乳液的黏度、粒径、稳定性和环氧值为最佳。 相似文献
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以双丙酮丙烯酰胺(DAAM)、丙烯酸(AA)为功能性单体合成了带酮羰基的聚丙烯酸酯核壳乳液,将其与己二酸二酰肼(ADH)、模板分子、致孔剂在室温下交联成膜制备出多孔结构分子印迹乳胶膜(MILM),比较了模板分子与功能单体之间的相互作用,研究了功能单体对MILM分离性能的影响。结果表明,用乳液室温交联成膜法可制备孔隙结构发达的分子印迹膜;三种功能单体与模板分子间相互作用强弱的排序为:ADH体系>DAAM体系>AA体系;ADH、AA和DAAM对MILM交联度的影响均较大,进而影响MILM的渗透性能;与非印迹膜比较,MILM对模板分子表现出选择识别性,分离因子可达到2.0以上。 相似文献
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以甲基丙烯酸全氟辛基乙酯(PFEA)为含氟丙烯酸酯单体,烯丙氧基壬基酚聚氧乙烯(10)醚单磷酸(ANPEO10-P1)为反应型乳化剂,采用预乳化、半连续法聚合方式合成了具有核壳结构的无皂含氟丙烯酸酯共聚乳液。研究了乳化剂用量对聚合反应以及PFEA用量对乳胶膜吸水率和接触角的影响。结果表明,当反应型乳化剂ANPEO10-P1用量为5%(质量分数,下同),PFEA用量为6%时,得到的乳液粒径分布窄,稳定性好,乳液成膜后吸水率低,达到8.8%,对水的接触角达到了109.5°,表现出优异的疏水性能。 相似文献
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以聚乙烯醇(PVA)为分散剂,丙烯酸丁酯(BA)、苯乙烯(St)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)、甲基丙烯酸(MAA)、丙烯酸十八酯(ODA)为原料,采用无皂乳液聚合方法合成了聚乙烯醇接枝阳离子聚丙烯酸酯多元无皂乳液。对聚合物的结构、组成及性质进行了表征,研究了共聚物乳液的粒径及分布、黏度、流变性和涂膜力学性质。结果表明,聚乙烯醇接枝阳离子聚丙烯酸酯无皂乳液平均粒径为140.9 nm,粒径分布在120 nm~160 nm,黏度为10.2 mPa.s左右,涂膜拉伸强度可达5.3 MPa。 相似文献
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以酪素(CA)、双丙酮丙烯酰胺(DAAM)、甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、丙烯腈(AN)为原料,通过无皂乳液聚合制备了酪素接枝丙烯酸酯表面施胶剂,考察了酪素用量对乳液稳定性和纸张施胶度的影响,软硬单体比例和交联单体DAAM的加入量对纸张施胶度和表面物理强度的影响。结果表明,酪素为单体总量30%,软硬单体... 相似文献
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Liu C Andjelić S Zhou J Xu Y Vailhe C Vetrecin R 《Journal of materials science. Materials in medicine》2008,19(12):3481-3487
Melt viscosities of poly(p-dioxanone) (PPDO) samples having different molecular weights were studied using a controlled-strain rotational rheometer
under a nitrogen atmosphere. First, PPDO’s thermal stability was evaluated by recording changes in its viscosity with time.
The result, that samples’ viscosities decreased with time when heated, demonstrated that PPDO is thermally unstable: its degradation
activation energy, obtained by using a modified MacCallum equation, was a relatively low 71.8 kJ/mol K. Next, viscoelastic
information was acquired through dynamic frequency measurements, which showed a shear thinning behavior among high molecular
weight PPDOs, but a Newtonian flow behavior in a low molecular weight polymer (M
w = 18 kDa). Dynamic viscosity values were transferred to steady shear viscosities according to the Cox–Merz rule, and zero
shear viscosities were derived according to the Cross model with a shear thinning index of 0.80. Then flow activation energy
(48 kJ/mol K) was extrapolated for PPDO melts using an Arrhenius type equation. This activation energy is independent of polymer
molecular weight. A linear relationship between zero shear viscosity and molecular weight was obtained using a double-logarithmic
plot with a slope of 4.0, which is near the usually observed value of 3.4 for entangled linear polymers. Finally, the rheological
behaviors of PPDO polymer blends having bimodal molecular weight distributions were investigated, with the results indicating
that the relationship between zero shear viscosity and low molecular weight composition fraction can be described with a Christov
model. 相似文献
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Readul Mohammad Islam Christopher Abadie Nazimuddin M. Wasiuddin 《International Journal of Pavement Engineering》2017,18(12):1122-1129
Viscosity determination of thixotropic emulsions with good repeatability has always been a major challenge. Currently, Saybolt Furol viscometer (SFV) is used to determine the viscosity of the emulsion, but the main drawback of the SFV is that it cannot simulate the behaviour of emulsion under different shear rate. Rotational viscometer (RV) can measure viscosity at different shear rates. Due to the thixotropic behaviour of the emulsions, getting repeatable results by following the hot binder specification is a problematic task. In this study, a new multiple shear step approach is used to determine the viscosity of the emulsified asphalt using RV. Three low viscous (SS-1, SS-1H and SS-1L) and two high viscous (CRS-2 and CRS-2P) emulsions were used in this study. Shear stress is gradually stepped up to different levels after certain time interval to determine the viscosity. In this manner, emulsion undergoes a known shear state and each reading is preceded by a certain repeatable shear history. It was observed that with the progression of time and simultaneous increase in shear rate, the viscosity results are much more stable and repeatable with less than 5% coefficient of variance. The final specifications proposed are 220–730 and 5–90 cP at 50 rpm and 30 °C for high and low viscous emulsions, respectively, which are based on 98% probability. Viscosity measured by this approach also showed strong correlation with water content (R2 > 0.94). The correlation between viscosity and water content is even stronger after dilution. With different dilution water content, viscosity of CRS-2 and CRS-2P exhibited R2 values of 0.97 and 0.98, respectively. 相似文献
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