超临界CO_2法制备乙酸纤维素微孔膜

以超临界CO2为非溶剂,丙酮和N, N-二甲基甲酰胺（DMF）为溶剂,制备了乙酸纤维素（CA）微孔膜,采用扫描电镜表征膜的微观形态并测定了膜的纯水通量,考察了溶剂与CO2的亲和性、CA质量分数、成膜压力、成膜温度、保压时间和卸压速度等因素对膜形态及性能的影响。实验结果表明,以丙酮为溶剂可制备出表观形态均一完整的膜;随着CA质量分数的增加,膜孔径变小,膜的水通量迅速降低;随着成膜压力、成膜温度的升高,膜水通量均先增加后减小;保压时间及卸压速度对膜水通量的影响较小。当CA质量分数为10 %时,在成膜压力为15 MPa,成膜温度为45 ˚C,保压45 min,快速卸压的操作条件下,微孔CA膜的水通量可达30 L·m-2·min-1。     

聚氟乙烯薄膜后处理工艺研究

考察了聚氟乙烯（PVF）薄膜干燥过程中溶剂初始含量、干燥温度对干燥前膜中溶剂含量和PVF膜的力学性能的影响。结果表明,干燥温度升高和溶剂初始含量减少会导致薄膜力学性能下降。当干燥温度为100℃时,采用配方4成型的PVF薄膜力学性能最佳。     

完全降解水溶性薄膜的制备

本文在选择好适宜的成膜料的基础上,以淀粉为主体材料,添加适当的增塑剂、防黏剂、表面活性剂、快干剂、水等,通过流延法成型而制备了可完全降解型水溶性薄膜。     

γ-丁内酯对PVF薄膜制备工艺及性能的影响

系统地研究了在聚氟乙烯薄膜的制备过程中,γ-丁内酯的添加对薄膜加工工艺及性能的影响。实验结果表明,γ-丁内酯作为PVF的潜溶剂可以显著地降低PVF的熔融温度,有效地阻止加工过程中PVF的热降解。通过拉伸测试可知,流延薄膜中γ-丁内酯的剩余含量是影响薄膜能否进一步拉伸的关键因素。挥发性能测试表明,γ-丁内酯在薄膜热处理过程中的挥发速率会严重影响薄膜的力学和光学性能。     

可交联型含氟嵌段共聚物的ATRP法制备及其在疏水涂膜中的应用

研究采用ATRP法制备了可交联型含氟嵌段共聚物P(MMA-HEMA-BMA)-b-PFMA,并考察了选择性溶剂的种类和成膜温度对聚合物胶束形态、涂膜表面微观结构形貌、涂膜疏水性和综合性能的影响。研究结果表明:在THF、DMF、F113、TFPE中含氟嵌段共聚物均能形成核壳结构胶束,胶束溶液成膜后涂膜表面具有一定微观粗糙结构。当以TFPE为溶剂,成膜温度为80℃时,含氟官能团能迁移到含氟嵌段共聚物的表面,涂膜表面的静态水接触角最大为135.2°,涂膜附着力为1级,硬度为HB,表现出优良的综合性能。     

溶剂对PVDF-g-PNIPAAm成膜过程及膜性能的影响

研究了不同溶剂种类对PVDF-g-PNIPAAm共聚膜的成膜过程及结构性能的影响,结果表明,DMF为制备PVDF-g-PNIPAAm共聚膜的最佳溶剂。     

PVC薄膜自黏性研究

采用流延法制备了聚氯乙烯（PVC）自黏膜,通过数字高阻计、原子力显微镜、视频光学接触角测量仪、傅里叶红外光谱仪等研究了增塑剂邻苯二甲酸二辛酯（DOP）含量、增黏剂种类及含量、薄膜厚度、表面粗糙度、表面张力、表面析出物对PVC膜自黏性的影响。结果表明,PVC膜的自黏强度随增塑剂含量增加而增加;增黏剂的加入极大地改善了PVC膜的自黏性,其中萜烯树脂増黏效果最好;PVC膜的自黏性与薄膜的表面能有很大的关系。     

大麻落麻纤维素膜制备及性能

将大麻长麻纺过程中产生的落麻溶解在氢氧化钠/硫脲/尿素水溶液中得到再生纤维素纺丝原液，通过相转化法制备出大麻落麻再生纤维素膜，并对大麻落麻纤维素的提取、溶解性能、成膜效果及再生纤维素膜的结构和性能进行研究。根据各项研究结果得出：4%浓度碱液处理后的大麻落麻纤维的纤维纯度较高，一定条件下能很好的溶解于氢氧化钠/硫脲/尿素溶剂中；当纤维素浓度达到6%时，可得到形貌较好的纤维素薄膜；纤维素经溶解制膜后，纤维素膜在较大程度上仍保留着纤维素的特征，纤维素晶型从纤维素Ⅰ转变为纤维素Ⅱ，纤维素薄膜的表面呈波纹状，并具有不均匀的多层结构。     

正硅酸乙酯对锐钛矿型二氧化钛多孔薄膜的室温制备及性能的影响

为在室温下制备具有良好多孔性的结晶二氧化钛(TiO2)薄膜,利用异相凝聚的方法将锐钛矿晶型TiO2溶胶粒子包覆在苯丙乳液粒子表面,并添加正硅酸乙酯(tetraethyl orthosilicate, TEOS)制得涂膜液.通过浸渍提拉法制备薄膜,随后在超声波振荡条件下,以甲苯为溶剂,将薄膜中的苯丙乳液粒子选择性地溶解去除获得多孔结构.对薄膜的表面形貌及光催化性能进行了考察,并分析了TEOS对薄膜制备及性能的影响.结果表明:添加TEOS的加入能提高涂膜液的成膜性,适量的TEOS有利于形成具有密集孔洞的TiO2薄膜.随TEOS添加量的提高,薄膜趋于平整,薄膜的透光率增大;光催化活性则随TEOS添加量先增大、后减小,其变化规律主要由薄膜多孔性,薄膜中TiO2含量以及薄膜的表面羟基数量等因素所决定.     

酰胺类溶剂对聚偏氟乙烯耐碱腐蚀性的影响

采用N,N-二甲基甲酰胺(DMF)、N-甲基吡咯烷酮(NMP)为溶剂制备了聚偏氟乙烯(PVDF)薄膜,采用色差、FT-IR的分析方法,研究了PVDF薄膜在氢氧化钠水溶液中的碱腐蚀行为。结果表明:溶剂法PVDF的耐碱腐蚀性能远低于热压法PVDF,残留溶剂NMP、DMF可加剧PVDF的碱腐蚀,并在PVDF表面产生了共轭多烯结构。酰胺类溶剂NMP、DMF遇碱分解生成的有机胺是导致溶剂法PVDF不耐碱腐蚀的根本原因。添加5%的氟碳阴离子表面活性剂可有效解决溶剂法PVDF不耐碱腐蚀的问题。     

吹塑成型PVF薄膜工艺研究

研究了采用挤出吹塑法成型聚氟乙烯薄膜的工艺；并结合制品性能，详细讨论了吹塑工艺参数的优化。结果表明，借助适当的潜溶剂和稳定剂，聚氟乙烯树脂在较高温度下具有很好的挤出加工性能。而采用双螺杆造粒一单螺杆吹膜的工艺流程，可以连续高效地成型出聚氟乙烯薄膜。     

The crystalline phase transformation of poly(vinylidene fluoride)/poly(vinyl fluoride) blend films

Poly(vinylidene fluoride) (PVDF), poly(vinyl fluoride) (PVF), and their blends were prepared by solution casting, followed by quenching in ice water after melting to obtain an α-crystalline phase. The films were drawn by solid state extrusion at two different drawing temperatures, 50°C and 110°C. The crystalline phases were analyzed by DSC and FTIR. In the undrawn films, the content of β-crystalline phase in the blend of PVDF/PVF 88.5/11.5 was higher than in the PVDF homopolymer, but it was lower than in the PVDF film with a draw ratio higher than 4. The α-crystalline phase in PVDF/PVF blends was mostly transformed into the β-crystalline phase beyond a draw ratio of 4, regardless of the draw temperature and PVF content. The α-crystalline phase of PVDF systematically transformed into the β-crystalline phase with increasing draw ratio. The crystallinity of PVDF/PVF blend films drawn at 110°C was higher than those drawn at 50°C. In the drawn blend films, characteristic IR bands of the α form were shifted to those of the β form and completely changed into those of β form at draw ratio of 4, regardless of the draw temperature and PVF content.     

凝胶挤出流延聚氟乙烯薄膜的研究

介绍了一种适合聚氟乙烯薄膜生产制造的新工艺——凝胶挤出流延法。该工艺克服了聚氟乙烯自身结构特性给成型带来的困难，得到的薄膜产品具有耐候性强、强度高、透光率大等优点，并有很好的应用前景。此外还系统讨论了树脂结构、潜溶剂及加工条件对薄膜制品的影响。     

The effect of some fluoropolymers' structures on their response to UV irradiation

The response of three commercial fluoropolymer films, untreated and γ-irradiated poly(vinyl fluoride) (PVF), poly(vinylidene fluoride) (PVDF), and poly(ethylene-co-tetrafluoroethylene) (ETFE), to ultraviolet (UV) irradiation was studied. The changes in tensile properties, thermal behavior, and chemical structure were investigated. The UV resistance of the PVF film is the lowest, and that of ETFE is the highest among the studied films. The biaxially oriented PVF films undergo massive chain scission under the UV irradiation. The chain scission process in both oriented PVF and PVDF films, although at different levels, is accompanied by increased solubility, increased upper glass transition temperatures, and decreased elevated temperature shrinkage. The UV exposure at 50°C, above the polymers' T_g has annealing effects, mainly reflected by a shift to higher temperatures of their upper glass transition. PVF films are unaffected by a low-dose ionizing radiation. However, the γ-irradiated films show reduction of their UV resistance. PVDF films undergo both chain scission and crosslinking by γ radiation, and the addition of UV exposure mainly causes further chain scission. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 1471–1481, 1998     

Influences of molecular weight and particle morphology on film processing properties of polyvinyl fluoride

To select a suitable kind of resin for preparing films, the melting point (T_m), thermal decomposition temperature (T_d), and stretch property of polyvinyl fluoride (PVF) as a function of the viscosity–average molecular weight (M_η) were investigated. The results showed that T_d and maximal stretch ratio of extrusion‐cast PVF films gradually increase with the increase of M_η. T_m also increases when M_η is below 400,000, but keeps invariable when M_η is beyond 400,000. Six different kinds of PVF resin samples in this article were classified into three types, according to their particle morphologies: (1) loose‐structured PVF (PVF‐A and G); (2) tight‐structured PVF (PVF‐F); and (3) intermediate‐structured PVF (PVF‐B, E, and H). The effects of the morphology on the solvent absorbability of PVF were studied. The results indicated that the loose‐structured PVF has better absorption capacity to solvent than does tight‐structured PVF. The processing temperature can be considerably reduced when N,N‐dimethylformamide (DMF) as a plasticizer was mixed with PVF, and the diminished magnitude depends on the absorption capacity of PVF to DMF. The evaporation of DMF is influenced by both molecular weight and particle morphology of PVF, and the final residue of DMF in the PVF/DMF mixture is dependent on the molecular weight of PVF. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1780–1786, 2006     

Effects of Plasticizers and Stabilizers on Thermal Stability of Polyvinyl Fluoride

The study was focused on the choosing of plasticizers and stabilizers for improving thermal stability of polyvinyl fluoride (PVF) during the thermoplastic processing. Five kinds of organic esters as plasticizers for PVF were evaluated. The results showed that dimethyl phthalate (DMP) had better compatibility with PVF and phase separation didn't occur up to a relatively high concentration level, and DMP significantly decreased the melting temperature of PVF and showed the good plasticized effect. The optimum DMP content, considering homogeneous compound, good melt fluidity, and dynamic thermal stabilization, can be determined from the melt flow index and torque measurements. Five kinds of additives as stabilizers for PVF/DMP system were evaluated by the color change during static ageing. It was found that pentaerythritol had remarkably positive effects on both thermal and color stability of PVF.     

Porous poly(vinyl formal) foam prepared using poly(vinyl alcohol) of low degree of polymerization

Poly(vinyl formal) (PVF) foams are usually prepared using poly(vinyl alcohol) (PVA) of high degree of polymerization, the most reported degree of polymerization being 1700. In the work reported, PVA of low degree of polymerization of 500 was used to prepare PVF foams, which is a great challenge because of the weaker hydrogen bond interaction than that for a higher degree of polymerization. By changing the concentration (from 10 to 20 wt%) of PVA solution, PVF foams were successfully obtained. It was found that a higher PVA concentration prevented foam volume shrinkage and the best concentration was 16 wt%. Scanning electron microscopy showed that the PVF foams had two kinds of pore structures, closed and open cell. The water absorption capacity and thermal properties of the PVF foams were carefully investigated. © 2018 Society of Chemical Industry     

RF sputter deposition of poly(tetrafluoroethylene) films as masking materials for silicon micromachining

Polymers have been studied extensively because of their wonderful array of properties. Their properties can be tailored by many means and can be made useful in many ways. Polymers can be crosslinked or branched and can provide different properties, such as conduction and passivation. This study dealt with the RF sputter deposition of poly(tetrafluoroethylene) (PTFE) films with the aim of using them as masking materials during the fabrication of various micromachined structures. The films were deposited on silicon substrates at different plasma powers (100, 150, and 200 W) for a constant deposition time (60 min). To test the masking properties, the deposited films were immersed in a 20 wt % aqueous KOH solution at 80°C for 60 min. The films showed lower contact angles and interfacial tension, and this indicated good adhesion of the films to the silicon substrates. Good adhesion is an essential quality of masking materials during micromachining. The structural properties of the as‐deposited and etched films were studied with Fourier transform infrared and X‐ray photoelectron spectroscopy. These indicated that the bonding groups and binding energies of C? F and C? CF matched the reported values well. Furthermore, the presence of C? F and C? CF bonds, even after the etching of silicon substrates in highly alkaline KOH solutions for 60 min, showed that the PTFE films remained unchanged in the etchant and, therefore, could function as good masking materials during the fabrication of micromachined structures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1183–1192, 2004     

Urushiol-formaldehyde polymer microporous films with acid-alkali resistance property: Effects of formation conditions on surface morphologies

Chinese lacquer, a natural polymeric material, and its processing products have been principally used to coat objects of high artistic and pleasing beauty with excellent physico-mechanical properties for centuries. The use of modified urushiol as functional materials, however, is rarely reported in the previous literature. To develop their potentially functional applications, the microporous films of urushiol-formaldehyde polymer (UFP) were fabricated on a solid substrate by using water-assisted assembly method in this paper. The resulted films were characterized by SEM and contact angle measurements. Several influencing factors were considered on the formation of the microporous films with different morphologies, including the concentration of the polymer solution, the relative humidity in the atmosphere, the speed of the moist airflow and the spread volume of the polymer solution. It was found that the pore size of microporous films increased with the increase of relative humidity, the speed of the moisture airflow, and the amount of the solution. Additionally, the ordered pores of UFP films could be formed even under the high concentrations. Furthermore, the as-prepared UFP microporous films had hydrophobic property and good acid-alkali resistance.     

聚乙烯醇缩甲醛吸水泡沫塑料的制备及性能研究

以淀粉为成孔剂制备了聚乙烯醇缩甲醛(PVF)泡沫塑料,研究了聚乙烯醇(PVA)种类及用量、淀粉种类及用量、甲醛与硫酸用量等因素对泡沫塑料性能的影响,并对泡沫塑料的泡孔的形态结构进行了分析。结果表明,不同成分条件下制备的泡沫塑料具有不同的密度、硬度和回弹性。该泡沫塑料是一种具有市场前景的良好的吸水材料。