PVB树脂各种粘度检测方法的探讨

对于PVB树脂,由于没有统一标准,各个厂家产品检测方法不同,造成了PVB客户选型难的问题。尤其是粘度指标,每个生产厂家检测方法与数据大相径庭。通过实验研究PVB树脂各种常见的检测方法并得到数据,再做出回归方程,只要将某检测方法的数据代入方程便可以计算出各种不同方法的粘度结果,最终便于确定产品型号。     

浅谈PVB树脂粘度的影响因素与控制

简要介绍了PVB树脂粘度的影响因素,主要包括原料PVA的聚合度、醇解度、PVA原液的浓度、综合反应的温度、醛化度等,并简要阐述了控制PVB树脂粘度的几种有效措施。     

聚乙烯醇缩丁醛合成工艺探讨

为了改进现有聚乙烯醇缩丁醛的合成工艺,探讨了丁醛与聚乙烯醇的配比、盐酸的用量、加料方式、反应助剂等因素对缩醛反应的影响。在优选的工艺条件下,产品的缩丁醛基质量分数可达77.2%,较原工艺提高了4.6%,产品粒径均一,无粘连。     

聚乙烯醇缩丁醛的制备研究

聚乙烯醇缩丁醛被广泛应用于油墨、花瓷、水松纸涂料、安全玻璃等许多领域,在国内外都有较好的应用市场。本实验通过对加料方式（加酸顺序）的探讨,发现后加酸优于先加酸。并且在m（PVA）∶m（正丁醛）=10∶7、反应体系pH值为3.0及缓慢滴加正丁醛的条件下,通过测定PVB胶粘剂的缩丁醛基含量和黏度,优选出制备PVB胶粘剂的最佳工艺条件。在以上条件都不变的情况下,使用聚合度为2099的PVA反应合成PVB的黏度和缩丁醛基的含量大大高于其他聚合度的PVA。     

共混比及聚合物浓度对PVC/PVB相容性及超滤膜性能结构的影响

通过混合焓的计算,对不同共混比和聚合物浓度的聚氯乙烯(PVC)/聚乙烯醇缩丁醛(PVB)共混比体系的相容性进行预测,并通过稀溶液黏度(DSV)法、运动黏度法和目视法进行相应验证;以N,N-二甲基乙酰胺(DMAc)为溶剂,通过湿相转换法(NIPS)制备PVC/PVB共混平板超滤膜,并对超滤膜的性能和结构进行测试,系统地研究了PVC/PVB共混铸膜液的组成对平板超滤膜的结构及其分离性能的影响,为通过PVB共混改性PVC膜材料制备超滤膜提供了理论依据。     

聚乙烯醇缩丁醛的生产及应用前景

介绍了聚乙烯醇缩丁醛树脂(PVB树脂)的理化性质、制备方法及其进展,并概述了其在安全玻璃夹层材料、特种涂料、黏合剂、陶瓷印花纸以及铝箔纸等方面的广泛用途。     

对影响聚乙烯醇缩丁醛产品质量稳定性因素的探讨

简述了聚乙烯醇缩丁醛生产的工艺流程。探讨了聚乙烯缩丁醛产品质量不稳定的原因。提出了水洗工序是PVB产品质量稳定的关键工序。     

火焰原子吸收光谱法测定PVB树脂中杂质Na的研究

聚乙烯醇缩丁醛树脂(Polyvinybutyrai,以下简称PVB,),是以聚乙烯醇(PVA)和丁醛为合成原料,以盐酸为催化剂缩合成的高分子化合物[1],工艺流程如图1.     

由气体粘度提供Lennard-Jones(12-6)势能参数

Lennard Jones ( 12 6)模型是最常用的势能模型 ,被广泛地用于工程计算和科学研究。Svehla在 1962年提供的 2 0 6种物质的Lennard Jones ( 12 6)模型的势能参数一直沿用至今 ;其中 ,最主要也认为最可靠的来源都是由气体的常压粘度数据求得的。自Svehla的工作以后又有许多新的气体的粘度数据发表 ,该文根据新的气体粘度数据提供了 63种物质的Lennard Jones ( 12 6)势能参数。所有采用的气体粘度数据都是经过评选的实测数据 ,利用新的Lennard Jones ( 12 6)势能参数计算气体粘度比用Svehla的数据要好。另外 ,文中发现由气体粘度数据求取的Lennard Jones ( 12 6)势能参数数据质量较高     

2-甲基-1,3-丙二醇水溶液密度和粘度的测定及关联

常压下采用密度瓶测定了纯液体2-甲基-1,3-丙二醇(MPO)及不同浓度的MPO 水二元体系在298.15~367.15K范围的密度;用乌氏粘度计测定了纯液体MPO及该二元体系在相应温度下的粘度.结果表明:MPO及其水溶液的密度和粘度均随温度升高而减小,密度呈线性衰减,粘度呈指数衰减;一定温度下MPO 水二元体系的密度随浓度变化大约在70%处出现了一极大值. 同时分别由密度和粘度实验数据计算了不同温度及组成下该二元体系的超额摩尔体积V E和混合粘度变化△η,结果V E和△η均为负值, 说明产生了负偏差.并由实验数据拟合出Grunberg-Nissan模型中的MPO-水体系的二元交互参数△Gij,它与温度和组成均有关.     

聚乙烯醇缩丁醛胶粘剂的制备

以聚乙烯醇(PVA)与正丁醛的质量比、反应体系的pH值、反应温度以及保温时间等作为制备聚乙烯醇缩丁醛(PVB)及其胶粘剂的主要因素,通过测定PVB的缩丁醛基含量、PVB胶粘剂的某些性能(如持粘力、黏度和固含量等)优选出制备PVB胶粘剂的最佳工艺条件。结果表明:当m(PVA)∶m(正丁醛)=100∶70、反应体系的pH值为2.0、反应温度为85℃、保温时间为3 h以及正丁醛的滴加速率为20~30滴/min时,PVB的缩醛度较高且形态较好,PVB胶粘剂的持粘力、黏度和固含量等指标均相对较高。     

Synthesis and characterization of PVB/silica nanofibers by electrospinning process

This paper describes PVB/silica nanofibers which were fabricated by electrospinning. Although electrospinning has developed rapidly over the past few years, electrospinning nanofibers are still at a premature research stage which is a process by which polymer nanofibers can be formed when a droplet of viscoelastic polymer solution is subjected to high voltage electrostatic field. PVB/silica nanofibers were obtained when the PVB/silica precursor ratio was 15% and the average diameters ranged from 100 to 200 nm and increased with increasing solution concentration and electrospinning synthesized at 12 kV of the applied voltage. The morphologies and structures of PVB/silica nanofibers were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), Fourier transform infrared spectrometer (FTIR), energy dispersive spectrometer (EDS).     

PVB／纳米TiO2复合材料的制备和表征

制备了不同聚乙烯醇浓度的聚乙烯醇缩丁醛（PVB），利用偶联剂和超声波分散法对纳米二氧化钛（TiO2）进行了表面处理，用共混法制备了PVB／纳米TiO2复合材料。采用红外光谱、X射线衍射、扫描电镜等表征了复合材料的红外吸收性能、光学性能、结构和微观形貌，测试了复合材料的力学性能。结果表明：由于纳米TiO2粒子的加入，复合材料的韧性得到明显提高，其断裂伸长率为纯PVB的6-8倍左右，同时使PVB／纳米TiO2复合材料具有良好的紫外线屏蔽性能。     

原位聚合法制备PVB/纳米Ti02复合材料及其性能与表征

利用韶声波分散法将纳米_氧化认(TiO2)均匀分散到聚乙烯醇(PVA)水溶液中,通过原位法制备了一系列不同TiO2含量的聚乙烯醇缩丁醛(PVB)纳米TiO2复合材料。采用FT-IR, UV-VIS, DSC和TG,AFM等平段对所制得的原位复合材料的结构、微观形貌和性能讲行了研究。结果表明,在合成PVB讨程中引入纳米Ti( )>粒子,能更均匀地分散在PVB笨质中,PVB对TiU粒子具有很奸的位理效果,形成了以纳米TiO2粒子为核心的网络结构。该原位复合材料的力学性能尤其是韧性得到了明显捍高,在TiO2相对PVB含量较低时其断裂伸长率就达到纯PVB的6倍左右,同时该复合材料具有良奸的紫外屏蔽性能及耐热性能,而且材料溶解后的诱明度良奸。     

Spatial distribution of lamella structure in PCL/PVB band spherulite investigated with microbeam small- and wide-angle X-ray scattering

The microbeam small- and wide-angle X-ray scattering (SAXS/WAXS) technique gives the novel information about micron-scale structural inhomogeneity of polymer crystal. By using this technique, we have studied structural inhomogeneity of lamella within the band spherulite of miscible polymer blend poly(ε caprolactone) (PCL)/poly(vinyl butyral) (PVB) and the structure development of lamella during crystallization. It is known that PCL/PVB forms very large spherulites (∼several mm in radius) with highly regular band structure because of low frequency of nucleation and that PCL/PVB crystallized at 41 °C has at least two kinds of lamella structure (150 Å, 180 Å). With an X-ray microbeam initially fixed outside near the growth front of the band spherulite, we have observed the lamella formation at the local point and have found that the larger long period grows before the appearance of the shorter long period. We have also observed that the orientation of lamella with the larger long period is different from that of lamella with the shorter long period from SAXS experiment with an X-ray microbeam scanning the band spherulite along its radial direction. Further, the discontinuity in lamella twisting was observed from scanning microbeam WAXS. Based on the experimental results, we propose two possible spatial distribution models. The result of PCL/PVB crystallized at 35 °C was also discussed.     

低聚合度、低醇解度聚乙烯醇的合成与性能研究——I.低聚合度聚醋酸乙烯酯的合成

以甲醇为溶剂,偶氮二异丁腈(AIBN)为引发剂,采用自由基聚合方法合成了低聚合度聚醋酸乙烯酯,并对其结构进行了表征。讨论了聚合时间、引发剂用量、物料配比、聚合温度等因素对聚合率的影响,获得了相对较佳的工艺参数。     

聚乙烯醇醇解度测定的定量核磁共振技术研究

建立了新的测定聚乙烯醇醇解度的定量核磁共振技术(QNMR)。结果表明:在实验温度303 K、脉冲等待时间2 s时,定量核磁共振方法得到的结果与滴定法十分吻合,而且精密度、重复性、稳定性均能达到要求。该方法具有快速准确、操作简便,不需对样品进行分离,可直接分析等特点。     

旋转管式膜分离技术的应用与研究进展

介绍了旋转管式膜分离器在工业生产中的应用,论述了膜器分离性能和机理以及膜器环隙间流场的国外研究现状和进展,并指出了今后进一步研究的方向。     

The effect of degree of polymerization on the structure and properties of polyvinyl alcohol fibers with high strength and high modulus

Polyvinyl alcohol (PVA) fibers were prepared using PVA with different degree of polymerization (DP) under the same wet spinning process. The effect of the DP of PVA on the structures and properties of PVA and PVA fibers were studied by using nuclear magnetic resonance hydrogen spectroscopy (¹H-NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimeter (DSC), thermo gravimetric analysis (TGA), and environmental scanning electron microscope (ESEM). The results showed that DP had little effect on the crystallinity and tacticity of PVA, but had a positive effect on melting temperature, and initial decomposition temperature of PVAs. The hot drawing ratio determined by the spinning process where the PVA fibers could be continuously collected without breaking. The drawing ratio was decreased with an increase of DP, resulting in an increase of the final fiber diameter. The PVA fibers with medium DP and medium size demonstrated high strength and high modulus, but relatively low breaking elongation. It suggested that high DP of PVA was not a guarantee of high strength and high modulus PVA fibers, but rather a primary structure factor. The fiber performance was determined by a comprehensive effect combining a variety of factors including polymer properties and spinning conditions. It provided a guideline for PVA fiber manufacture that the PVAs with different DP require different spinning processes to obtain optimal fiber performance.     

Electrical conductivity of LTA‐zeolite in the presence of poly(vinyl alcohol) and poly(vinyl pyrrolidone) polymers

In this work we studied the electrical behavior of Linde type A zeolite (K⁺) in the presence of two polymers, poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP), with excellent film forming properties. Homogeneous composite thin films of PVA/LTA‐zeolite and PVP/LTA‐zeolite were prepared with different zeolite concentrations. The current?voltage (I?V) characteristics of the composites were measured at different applied voltages. The results show that the conductivity properties are composition‐ratio‐dependent and are also related to the type of polymers. Moreover, a well‐defined step‐like change was detected in the I?V curve of PVP/LTA‐zeolite at very high applied voltage. © 2013 Society of Chemical Industry