柠檬酸改性对变色聚乙烯醇流延膜性能的影响

以聚乙烯醇（PVA）为母液、柠檬酸为交联剂制备了变色PVA流延膜,并对薄膜的力学性能、光学性能和热稳定性进行了研究。结果表明,随着柠檬酸质量分数的增大,薄膜的抗张强度增大,伸长量减小;随着柠檬酸质量分数的增加,薄膜的雾度呈上升趋势;柠檬酸质量分数对变色薄膜的颜色及颜色变化也有较大影响;添加柠檬酸提高了薄膜的热分解温度,从而提高了薄膜的热稳定性。     

橡胶型敷型涂料的制备及性能研究

以丁苯橡胶为主要成膜物,成功制备了一种新型橡胶型敷型涂料。考查了丁苯橡胶种类、增粘树脂种类及用量、涂膜厚度以及水汽温度对涂膜透湿率的影响。结果表明,以氢化SBS YH-502为主要成膜物,并添加100%的C5石油树脂,涂膜的透湿率最低。涂膜透湿率随涂膜厚度的增加而降低,随着水汽温度的提高而升高。     

聚乙烯醇为载体的吸湿塑料软包装技术

以聚乙烯醇为载体,分别加入增塑剂和甲基纤维素,通过流涎法制备吸湿薄膜。测试了薄膜的力学性能、透明度及吸湿性等。结果表明:增塑剂和甲基纤维素对薄膜的透明度影响较小,但是甲基纤维素对薄膜的雾度影响较大,雾度随着甲基纤维素添加量的增加而增加。     

高固体分低VOCs氟碳涂料的制备研究

采用高氟含量氟碳树脂,用于制备常温固化高固体分低VOCs氟碳涂料。通过制备不同氟含量高固体分低VOCs氟碳涂料的耐人工老化性、配套性、耐化学品性及物理性能等的检测,研究表明：（1）氟碳树脂中C—F键的螺旋包裹作用能有效提高涂膜的屏蔽和保护作用,氟含量的提高能有效增加涂膜的涂料耐化学品性及耐人工老化性;（2）氟碳树脂的低极性使制备涂膜表面张力低,提高氟含量可以提高涂膜与水的接触角,进而提升涂膜的耐沾污性;（3）由于氟碳树脂低极性较低,不同氟含量树脂制备氟碳涂料调整黏度时使用溶剂量不同,高氟含量树脂溶剂的加入量大,造成涂料体积固体分减低,VOCs增加;（4）氟碳涂料制备涂膜,随时间增长涂膜交联密度提升,拉伸率降低。     

添加聚乙烯醇改善三氧化钨电致变色薄膜性能的研究

为改善三氧化钨薄膜的电致变色性能,采用钨粉过氧化聚钨酸溶胶-凝胶法制备了添加聚乙烯醇的三氧化钨电致变色薄膜.采用扫描电镜、紫外可见分光光度计和CHI电化学工作站分别测定和分析了三氧化钨薄膜的微观结构、光透过性能和循环伏安特性.结果表明,添加一定量的聚乙烯醇可使薄膜的结构更加平整,变色更为均匀;在着色态、褪色态下的光透过率之差达到60%以上,变色可调范围变大.电致变色可逆性能和光谱性能较不添加聚乙烯醇有所提高.     

聚酯二元醇合成聚氯酯丙烯酸酯复合乳液的研究

以异佛尔酮二异氰酸酯（IPDI）、自制聚酯二元醇、二羟甲基丙酸（DMPA）和甲基丙烯酸甲酯（MMA）、苯乙烯（St）、丙烯酸丁酯（BA）为主要原料,合成了聚酯型聚氨酯丙烯酸酯（PUA）复合乳液,研究了不同相对分子质量的聚酯二元醇、聚氨酯制备时不同NCO／OH比值、添加三羟甲基丙烷（TMP）含量、及合成PUA时不同PU／PA的比值对最终制备的聚氨酯丙烯酸酯复合乳液及涂膜性能的影响。结果表明：1500～2000相对分子质量的聚酯二元醇：在TMP添加量为2％、NCO／OH为1．6～1．8,PU／PA以4：6合成出的PUA,有着较好的制备稳定性和贮存稳定性,其涂膜硬度、耐水性和耐醇性较好。     

阻隔性薄膜透气性能的压差法和等压法测试分析

利用压差法、等圧法研究了4种阻隔性塑料薄膜的氧气和二氧化碳气体透过量,分析了温度、薄膜类型和厚度、相对湿度对透气性能的影响关系,对比了2种测试方法的薄膜透氧量。结果表明,12 μmPET、12 μmPET/Al、25 μmPET和25 μmPVDC薄膜的氧气、二氧化碳气体的透过量都受温度影响显著,都随着温度的升高而增大,其对数形式与热力学温度的倒数都呈线性关系;这4种阻隔性薄膜对氧气、二氧化碳气体的透过性能都存在明显差异,12 μmPET薄膜的透过量最大,25 μmPET薄膜和25 μmPVDC薄膜次之,12 μmPET/Al薄膜最小,而且它们对二氧化碳和氧气的透过量之比值都超过了4倍,都具有优良的阻隔性能和选择透过性。     

PEG对TiO2薄膜光电特性的影响

研究添加第三组分对TiO2光电特性的调节规律对于研制新型气敏材料、太阳能电池等具有重要意义.本文采用溶胶-凝胶技术制备了添加聚乙二醇（PEG）的TiO2薄膜,研究了PEG的添加对晶体型态、表面形貌和半导体特性等的影响.结果表明,PEG的添加量与相对分子质量对TiO2薄膜的透光性有明显影响,添加PEG2000（2000为PEG的相对分子质量）的TiO2薄膜在350℃时对CO的气敏性达到3.5,这种p-型TiO2薄膜材料在太阳能电池、气敏传感器等领域有广阔的应用前景.     

大滞后可逆热致变色微胶囊的制备及性能研究

以结晶紫内酯(CVL)、双酚A(BPA)、2-(4-苄基氧基苯基)乙基癸酸酯(DAE)为芯材,以三聚氰胺-尿素-甲醛共聚树脂为壁材,以苯乙烯-马来酸酐共聚树脂(SMA)为乳化剂,制备了大滞后可逆热致变色微胶囊,并采用纳米粒度仪对微胶囊的大小进行了表征,同时采用DSC技术对微胶囊的热致变色机理进行了研究,并探讨了变色温度...     

乙基纤维素修饰的PEO薄膜等温结晶性能研究

采用乙基纤维素对PEO薄膜进行修饰,通过对修饰后PEO薄膜进行差示扫描量热测试,研究薄膜厚度变化对PEO等温结晶过程的影响。通过Avrami研究发现:乙基纤维素修饰的PEO薄膜厚度小于晶核间的平均距离时,Avrami图形在结晶初期出现了一个转折点,分析表明:该点是结晶体生长方式发生改变的转折点。     

Air Separation through Modified Ethyl Cellulose Thin Film Supported on Porous Polyethersulfone

Abstract

Composite membranes for air separation were prepared from a liquid crystal DYC-modified ethyl cellulose (EC) thin film ranging in thickness from 1 to 7 μm and a porous polyethersulfone support with a thickness of 120 μm. The effects of DYC/EC (9/91) solution concentration, water, and operating parameters such as temperature, pressure, and time on the air-separation properties of the composite membranes were examined by a constant pressure—variable volume method. The permeate flux and oxygen concentration of the oxygen-enriched air (OEA) through the membranes increase significantly with increasing operating pressure difference. With decreasing casting solution concentration, or with increasing humidity around the membranes or operating temperature, the OEA flux increases greatly while the oxygen concentration sometimes decrease slightly. An increase in the operating time leads to an OEA flux decline, but the oxygen concentration rose when the operating time was varied for 70 hours. However, a further increase of the operating time from 70 to 500 hours does not lead to further changes of the OEA flux and oxygen concentrations. A thin-film composite membrane exhibits a slightly lower oxygen concentration accompanied by a very significant enhancement in the OEA flux and membrane stability compared to a homogeneous dense membrane of the same materials.     

Air separation characteristics with liquid crystalline alkyl cellulose blend thin-film composite membranes

Composite membranes were made of liquid crystalline triheptyl cellulose (THC)/ethyl cellulose (EC) blends as dense thin films and poly(ether sulfone) (PES) or polysulfone (PSF) as porous support layer. The effects of the composite membrane composition and operating conditions on the air separation characteristics of oxygenenriched air (OEA) permeating through the membranes were studied using a constant pressure-variable volume method. The flux (OEA) through the membranes decreases slightly and the oxygen concentration in the OEA permeated increases with increasing THC content in the thin film from 4 to 15 wt.-%. The OEA flux increases significantly with decreasing thin-film thickness or increasing operating temperature and transmembrane pressure difference. The oxygen concentration in the OEA increases with increasing the thin-film thickness or the pressure difference but decreases slightly with increasing the operating temperature. There is no regular variation in the air separation properties by changing the support from PES to PSF. In long-term tests, the air separation properties remained almost constant for as long as 800 h. An OEA flux of 1.0–1.9·10^-3 cm³ (STP)/s·cm² containing 34.8–39.4 vol.-% oxygen can be attained at 30–55°C and 0.41–0.49 MPa pressure difference in a single pass through the membranes. The OEA flux is much higher for the thin-film composite membranes than for the homogeneous dense membranes made of the same materials.     

Waterborne latex coatings of color: III. Triblock polyether influences on color development and viscosity

Oxyethylene (PEO)/oxypropylene (PPO) triblock polymers are added to colorant formulations to determine the influence of molecular weight and other structural variances on the rheology and color development of tinted latex paints. Waterborne coatings are a matrix of many coating components. In this study, a 108- or a 600-nm latex was thickened with a nonassociative thickener, hydroxyethyl cellulose, or an associative telechelic HEUR thickener. Triblock polymers with internal PPO segments and PEO terminal segments added as a dispersant to colorant packages, lead to better color development than PPO/PEO/PPO triblocks dispersants in carbon black (CB) tinted paints. The increase in color development with high molecular weight (MW) triblocks starts at a very low concentration (2 mM) and plateaus in a Langmuir-type adsorption isotherm. Lower molecular weight triblock polymers also exhibit this behavior in CB-, red-, and yellow-tinted latex coatings; however, increasing the terminal PEO segment sizes leads to better color development only in the CB-tinted coatings. With large PEO terminal units red and yellow tints are high only at very low concentrations (2 mM) of the triblock. This parabolic response in color development, in contrast to CB-tinted formulations, is attributed to the high surface area and porosity of CB that limits the amount of large PEO segments interacting with the talc particle present at twice the volume fraction of the colorant. With the lower surface areas of the red and yellow colorants, the interaction of the large PEO terminal segments with talc particles accounts for the limited triblock concentration for which good color development is observed. This can be reversed by decreasing or eliminating talc from the formulation.     

聚酰胺酸溶液成膜过程中的传质行为

为了研究聚酰胺酸溶液成膜过程中的传质行为,采用自制液膜干燥实验装置在线测定聚酰胺酸溶液质量的变化.假设气、液两相传质通量相等的条件下,计算了溶剂气相传质系数和液面蒸气压.在此基础上考察了干燥温度、液膜厚度、溶液相对分子质量对液膜表面蒸气压的影响.结果表明,成膜过程中存在溶剂蒸发与聚酰胺酸溶液亚胺化反应的相互竞争.干燥初期溶剂蒸气压迅速升高,液膜表面溶剂的扩散为控制步骤;而干燥后期溶剂蒸气压较小,溶剂在膜内部扩散成为控制步骤.同时随着液膜厚度的增加、干燥温度的升高及溶液相对分子质量的减少,液面蒸气压的最大值呈现增大趋势.     

Electrically conductive composites prepared from 3-methyl thiophene by the FeCl3 oxidation method

Surface conductive polyurethane films from poly(propylene glycol), toluene 2,4-diisocyanate, 3-methyl thiophene and butyltin dilaurate can be successfully prepared by the diffusion-oxidative polymerization method. Various effects of the doping conditions, such as the reaction time, the FeCl₃ concentration, the weight ratio of the 3-methyl thiophene to PU and the temperature on the electrical conductivity and thickness of the conductive layer of the 3-methyl thiophene/PU composite were investigated. Decomposition temperature rises gradually from pure undoped PU to doped composite that indicates blending took place in FeCl₃/ethyl acetate solution. As oxidative reaction time increases, the electrical conductivity of the 3-methyl thiophene doped PU film increases together with the thickness of the coating layer. With increasing FeCl₃ concentration and weight ratio of the 3-methyl thiophene to PU, the thickness of the coating layer decreases, while the electrical conductivity increases. The increase of the thickness of the PU film leads to the rise of the electrical conductivity. The thickness of the coating layer decreases, while the electrical conductivity of the 3-MT doped PU film increases with increasing reaction temperature. As the reaction time and temperature increase, the polar components of the PU film increase resulting into the increase of moisture regain value.     

Controlling Shell Thickness of PS/SiO2 Core-Shell Particles and Their Crystallization into 3-D Ordered Thin Film

PS/SiO2 particles with core-shell structure were synthesized by coating silica on surface of polystyrene (PS)colloidal particles. The reaction parameters, such as initial tetraethyl orthosilicate (TEOS) concentration, water concentration and reaction temperature, have been investigated to control the thickness of silica shells. The shell thickness was prepositional to the square root of the initial concentration of TEOS and first increased with increasing water concentration, reached a maximum at about 2.0 mol/L and then started decreasing beyond that concentration. It was also found that the shell thickness decreased firstly with the reaction temperature added, then tended to a constant. The so-synthesized PS/SiO2 core-shell particles were directly crystallized into 3-D ordered thin film, then sintered at 570 ℃ into the ordered macroporous thin film.Compared with the conditional method, the present approach avoids repeatedly filling the precursor in the templetes and save time more.     

Studies on syntheses and permeabilities of special polymer membranes.: 15. Permeation characteristics of nylon-12 cellulose acetate blends

The permeation characteristics of nylon-12-cellulose acetate polymer blend membranes in the separation of polymers, poly(vinyl alcohols), from their aqueous solutions were investigated under various conditions. The permeation characteristics were influenced markedly by the ratio of nylon-12-cellulose acetate, the feed concentration, the operating pressure and temperature. It was found that the changes of polymer ratio and the concentration of blended polymer were related to the change of microporous structure of the resulting membranes. When the cellulose acetate content was higher a significant compaction of the membrane occurred under pressure. It was found that there was a concentration polarization of poly(vinyl alcohol) molecules on the membrane surface, whose thickness increased with increase in molecular weight of poly(vinyl alcohol) and in feed concentration. The bursting strength of the polymer blend membranes swollen with water increased considerably as the cellulose acetate content in the blended polymer increased.     

胃溶型丙烯酸树脂乳液的制备

采用乳液聚合法,以甲基丙烯酸甲酯(MMA)和甲基丙烯酸二甲氨基乙酯(DM)为单体,制备了可直接用于药物包衣的胃溶型丙烯酸树脂乳液。结果表明,当温度为65℃,单体摩尔比为1∶1,引发剂和乳化剂用量分别为0.6%和0.3%,采用单体连续滴加法时,可制得稳定的乳液,聚合物分子量为14.9万。在180℃以下,产品的失重率基本不随温度而变,而在180℃以上,失重率随温度升高而增加。聚合物膜在缓冲溶液中的失重率随pH的增加而减小,当pH为1.0和2.0时,膜几乎全部溶解,pH为3.0时,膜的失重率为65.0%,在pH为4.0时,失重率迅速降低到32.8%,到pH为7.0时,膜已基本不溶。     

丁基橡胶聚合新型超重力反应器工艺

将新型旋转填充床反应器（RPB）应用于阳离子聚合制备丁基橡胶（IIR）过程。实验初步考察了旋转填充床转子转速（N）和聚合温度（T_p）等工艺参数对聚合产物IIR分子量和分子量分布的影响规律。研究结果表明：在实验条件下,当N=1200 r·min^-1、T_p=-100℃时,采用超重力法新工艺制备的IIR的数均分子量达到2.89×10⁵,分子量分布指数达到1.99。同时,物料停留时间小于1 s (现工艺30~60min),单位设备体积的生产效率提高了2~3个数量级。随着N的增大和T_p的降低,聚合产物IIR的分子量升高,而分子量分布变化不大。     

Multilayer ultrathin-film composite membranes for oxygen enrichment

Multilayer composite membranes were made of poly(4-methylpentene-1) (PMP), an ethyl cellulose (EC) + heptyl cellulose (HC) blend, polycarbonate (PC), polysulfone, poly(2,6-dimethylphenylene oxide), cellulose triacetate ultrathin films as selective layers, and polysulfone, poly(ether sulfone), and poly(sulfone amide) ultrafiltration membranes with a 10–45 nm pore size and 100–120 μm thickness as porous support layers. The effects of the ultrathin-film type and its casting solution concentration, operating pressure, temperature, as well as time on the oxygen-enriched air (OEA) flux and oxygen concentration in the OEA permeated in a single step through the composite membranes were investigated using a constant pressure—variable volume method. The OEA flux increases significantly with an increasing transmembrane pressure difference and operating temperature. The oxygen concentration in the OEA also increases with an increasing pressure difference but decreases slightly with an increasing operating temperature. In long-term tests, the oxygen-enrichment properties were maintained almost constant for as long as 170 h. The composite membranes consisting of the bilayer ultrathin film cast from a more dilute solution (0.11–0.26 wt %) on the porous support with a smaller pore size combine a higher oxygen-enriching ability and a higher stability than do those of monolayer and tetralayer ultrathin films. The maximum OEA flux and oxygen concentration produced at 20–75°C and a 500 kPa transmembrane pressure difference in a single pass across the PMP/98EC + 2HC bilayer and PC bilayer ultrathin-film composite membranes are 3.1 × 10⁻³ cm³(STP)/s cm² and 50%, respectively. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2139–2147, 1997