木质素/PVA复合膜的性能

以可再生资源木质素磺酸钙和聚乙烯醇(PVA)为基料,制备力学强度及耐水性能良好的木质素/PVA复合膜。采用5因素二次正交旋转组合设计研究了木质素磺酸钙、PVA、甲醛、尿素、硼砂对膜拉伸强度、断裂伸长率和吸水率的影响,并得到相应二次回归模型。分析表明:5个因素的一次项、二次项及交互项对膜拉伸强度、断裂伸长率和吸水率均有不同程度的影响。当原料配比为木质素磺酸钙7 g、PVA 14 g、甲醛10 g、尿素7 g、硼砂2.5 g时,可以得到拉伸性能和耐水性优良的木质素/PVA复合膜。     

纳米ZnO/纤维素纳米晶/聚乙烯醇复合膜的制备及性能

采用球磨法制备的纤维素纳米晶(CNC)及市售纳米ZnO对聚乙烯醇(PVA)进行改性,改善了PVA膜的力学性能,并且,赋予其抗菌性,测试复合膜的力学性能、水蒸气透过性能及抗菌性能。结果表明,加入CNC后,提高了PVA膜的力学性能和阻湿性能,加入纳米ZnO后,复合膜对金黄色葡萄球菌具有一定的抗菌性能,并且,能进一步提高复合膜的拉伸强度,但是,降低了复合膜的阻湿性能。当CNC的添加量为3%、纳米ZnO∶CNC=2∶1(摩尔比)时,复合膜综合性能较好,拉伸强度为73.7 MPa,与纯PVA膜相比,提高了77.2%;断裂伸长率为3.8%,与纯PVA膜相比,提高了46.1%;水蒸气透过系数为3.44×10^-13 g·cm/(cm²·s·Pa),与纯PVA膜相比,提高了11.7%。     

分离有机/有机混合物的PVA、CA系列膜及其渗透汽化性能研究(Ⅰ)膜材料与成膜工艺

依据溶度参数原则和分离甲基叔丁基醚(MTBE)/甲醇(MeOH)混合物的选择渗透性,选择了聚乙烯醇(PVA)为复合膜的分离层材料,聚丙烯腈(PAN)、醋酸纤维素(CA)系列为支撑层的膜材料.初步讨论了膜材料和复合膜结构对分离性能的影响,给出了用不同成膜工艺制备的膜性能,获得了可用于有机/有机体系分离的性能优良的PVA/PAN和PVA/CA复合膜,以及CTA中空纤维渗透汽化膜.     

木质素磺酸钙对硬化水泥抗压强度的影响

木质素磺酸盐(简称木盐)具有较强缓凝和引气作用,可提高混凝土工作性,但过量使用会导致混凝土抗压强度急剧下降。该文从掺量、相对分子质量、亲水基、金属阳离子和糖分5个方面研究了木质素磺酸钙(简称木钙)对硬化水泥抗压强度的影响规律。结果表明,随木钙掺量增加,硬化水泥的各龄期抗压强度均下降,掺量w(木钙)=0.5%时,硬化水泥的28 d抗压强度仅为空白浆体的63.6%。其中相对分子质量为1万~5万的木钙超滤级分对硬化水泥强度的降低作用较小。木钙中糖分质量分数由12.5%降至2.8%时,硬化水泥的7 d抗压强度比可提高16%。通过氧化将木钙分子中的羟基转化为羧基,硬化水泥的3、7、28 d抗压强度比分别提高22.1%、34.7%和13.0%;通过磺甲基化将木钙的磺化度由1.36 mmol/g提高到2.48 mmol/g,硬化水泥的3、7、28 d抗压强度比分别提高36.2%、41.2%和17.9%。     

全氟磺酸改性聚乙烯醇渗透汽化膜分离乙酸乙酯-水溶液

以聚乙烯醇(PVA)为原材料,全氟磺酸(PFSA)为共混改性材料,以聚丙烯腈(PAN)中空纤维超滤膜为底膜制备了PVAfPAN、PVA-PFSA/PAN复合膜,并用于乙酸乙酯脱水.考察了共混涂膜液中PVA、PFSA配比,交联剂酒石酸(Tat)用量以及原料液温度与浓度对PVA、PAN、PVA-PFSA、PAN复合膜分离件能的影响.实验结果表明,Tac交联的PVA,PAN、PVA-PFSA/PAN复合膜均对水具有较好的分离选择性.共混涂膜液中PVA/PFSA质量比为1/1、Tac/PVA质量比为l/5时所制备的PVA-PFSA/PAN复合膜渗透汽化分离性能最佳.40下℃此复合膜用于分离98%(wt)的乙酸乙酯水溶液时,其渗透通量和分离因予分别为81.1 g·m-2·h-1和1890.同样条件下,与交联PVA/PAN复合膜相比,交联PVA-PFSA/PAN复合膜的渗透通量显著提高.     

非木本木质素磺酸镁对水泥净浆和砂浆性能的影响

用红外光谱法等测定了非木本木质素磺酸镁的结构特征参数,研究了其对水泥净浆和砂浆性能的影响,并与木本木质素磺酸钙进行了对比。非木本木质素磺酸镁结构中的甲基、酚羟基、芳香环比木质素磺酸钙少;特性黏度为 0. 61mL/g,仅是木质素磺酸钙的 61%;磺化度为 0 78mmol/g,比木质素磺酸钙低约 40%。木质素磺酸镁溶液的最低表面张力为 49 82mN/m,起泡性能与木质素磺酸钙相近。非木本木质素磺酸镁对水泥净浆和砂浆减水分散作用为木本木质素磺酸钙的 86 6% ~91 1%。但掺质量分数 0 5%的木质素磺酸镁的砂浆, 28d的抗压强度比掺木质素磺酸钙的高 70 5%。     

纳米TiO_2对PVA/St复合膜性能的影响

为改善聚乙烯醇/淀粉(PVA/St)复合膜的力学性能、阻隔性能和降解性能,通过溶液浇铸法制备纳米二氧化钛改性的PVA/St复合膜(PVA/St/TiO_2),探究Ti O_2含量对PVA/St/TiO_2复合膜力学性能、水接触角、阻隔性和降解率的影响。结果表明:PVA/St/TiO_2复合膜制备成功,当TiO_2颗粒含量为1%,PVA/St/TiO_2复合膜综合性能较优。相比PVA/St复合膜,PVA/St/TiO_2(1%)的拉伸强度高达31.2 MPa,提高39.3%。PVA/St/TiO_2(1%)的水接触为110°,具有疏水性。PVA/St/TiO_2(1%)对水蒸气和氧气的透过率分别为3.2 g/(cm·s·Pa)和203 cm3/(cm2·d·0.1 MPa)。PVA/St/TiO_2(1%)经过120 d的降解率约为63%,与PVA/St复合膜相比提高14.5%。     

PHBV/PVA复合膜的制备及其性能研究

采用静电纺方法制备聚羟基丁酸/戊酸酯共聚物(PHBV)纤维膜材料,通过调节纺丝液中无水乙醇的含量制备出形态均匀的PHBV静电纺纤维膜。用浇铸法将聚乙烯醇(PVA)涂敷在PHBV静电纺纤维膜上,制备PHBV/PVA复合膜,通过调节PVA的浓度及涂覆量,研究复合膜配比对其力学性能及过滤性能的影响。结果表明,当PVA浓度为8%,PHBV/PVA体积比为2/3时,得到最佳性能的PHBV/PVA复合膜,水通量达到996 L/(m2.h),截留率为86%。     

聚乙烯醇-壳聚糖/有机累托石复合膜制备与性能

采用溶液共混法制备聚乙烯醇(PVA)-壳聚糖(CS)/有机化累托石(OREC)系列复合膜,以X-射线衍射、扫描电镜、透射电镜表征了复合膜的形貌结构,研究了复合膜的热性能、溶胀性能及对牛血清蛋白的吸附-缓释性能。实验结果表明,在OREC质量分数为2%,PVA质量分数为10%时,复合膜具有良好的插层结构,且热稳定性最好,吸水率及对牛血清蛋白吸附率最大,缓释性能最好。与纯CS膜相比,此复合膜40%失重率时对应的热分解温度提高133℃,溶胀率提高16.1 g/g,对牛血清蛋白的吸附率提高16.5 mg/g。     

新型PVA/PA复合膜的微结构及其成膜条件

将不同材料分别用作复合膜的分离层和支撑体,是制备优良选择渗透性分离膜的重要方法之一.采用浇铸工艺将具有亲水性和高分离因子的聚乙烯醇(PVA)涂覆在高度透水性的反渗透(RO)聚酰胺(PA)膜表面,制备成渗透汽化(PV)分离有机物水混合物的PVA/PA复合膜.扫描电子显微镜(SEM)和原子力显微镜(AFM)以及红外光谱分析表明,PVA-PA层结构为一体化,膜表面光滑、致密,分离层上的微囊高度下降到4 nm左右.可以认为膜的优异传质性能取决于良好微结构包括PVA的化学交联和膜的结构形貌.铸膜液中PVA和交联剂的浓度以及热处理条件对复合膜分离性能的影响是明显的.这一新型的复合膜在环境温度下PV分离异丙醇(IPA)/水混合物的渗透通量(J)接近100 g·m-2·h-1,渗透物中的水含量(CP-H2O)大于99.5%.     

Optical and structural properties of polyvinyl alcohol loaded with different concentrations of lignosulfonate

Polyvinyl alcohol/lignosulfonate (PVA/LS) composite films have been prepared using casting technique. The effect of lignosulfonate concentrations (0.001, 0.005, 0.01, 0.05, 0.1 and 0.5 wt %) on the optical and structural properties of polyvinyl alcohol (PVA) has been investigated using UV–vis spectroscopy and X‐ray diffraction. The results indicate that, the addition of LS led to a more compact structure of PVA, which resulted in an increase in its refractive index and amorphous phase. This was associated with a reduction in the optical energy gap that could be attributed to the increase in disorder structural of the composites. Moreover, the transmittance of PVA/LS composite film decreased with the increase of LS doping concentrations onto the PVA matrix. The results reflect the proper dispersion of LS in the PVA matrix that causes a strong intermolecular interaction between LS and PVA suggesting strong hydrogen bond formation between the hydroxyl group in PVA chains and the outer site groups of LS. Further, the transmission of the samples in the wavelength range of 370–780 nm, as well as any color changes, was studied. The color intensity ΔE, which is the color difference between the pure PVA sample and those with different LS concentration, increases with increasing the LS content and was accompanied by an increase in the yellow and red color components. J. VINYL ADDIT. TECHNOL., 25:85–90, 2019. © 2018 Society of Plastics Engineers     

木质素磺酸钠与PVA共混薄膜的制备与表征

以木质素磺酸钠(LS)和聚乙烯醇(PVA)为主要原料,添加适量硼砂、明胶在水溶液中溶解共混,流延成膜.通过单因素和正交实验优选了LS/PVA共混膜制备的条件,对共混膜进行了耐水性、形貌、红外、热重、X射线衍射及差示扫描量热分析.结果表明:影响共混膜性能的主要因素有LS含量、硼砂含量以及反应时间,当硼砂含量为2.0%时,...     

超声辐射对PVA/CB导电复合材料气敏性能的影响

以聚乙烯醇(PVA)为基体,填充各种类型炭黑导电粒子,制备了导电复合薄膜。研究了超声作用下导电复合薄膜在不同溶剂蒸气中的气敏性能。考察了PVA与炭黑的比例、炭黑种类、超声时间、超声功率等条件对导电薄膜响应性能与响应稳定性的影响,并对这种导电复合薄膜产生气敏响应性的机理作了分析。结果表明,以PVA/乙炔炭黑组成的导电复合薄膜具有较强气敏响应性。当将其置于丙酮、正丁醇、乙醇、水极性溶剂中,电阻急剧提高102~103倍,表现为正蒸气系数效应(PVC);随炭黑含量提高,复合材料薄膜室温电阻下降,对溶剂蒸气的响应强度提高;超声时间、功率对导电粒子分散行为及复合材料的气敏性有影响,随超声时间延长及功率增大,接枝改性效果明显,导电薄膜的响应性及重复稳定性提高。     

聚乙烯醇/淀粉/凤仙透骨草提取物复合膜制备及性能

以聚乙烯醇(Polyvinyl alcohol,PVA)、淀粉(Starch,ST)为原料,凤仙透骨草提取物(Impatiens balsamina extract,IBE)为抗菌剂,通过共混法制备抗菌复合膜,通过FTIR、XRD、SEM和热重分析对复合膜的形貌和结构进行表征及对力学、光学、阻隔、抑菌等性能测试分析。结果表明,IBE与PVA/ST基膜复合良好,制备的PVA/ST/IBE抗菌复合膜对大肠杆菌、白色葡萄球菌和枯草杆菌具有良好的抑菌作用,抑菌性能随着IBE含量的增加而逐渐提高；同时具有良好的力学强度,IBE添加量为12.5 mL的复合膜拉伸强度达到22.97±0.68 MPa,断裂伸长率相比PVA/ST基膜提升了79.22%；透明度有所下降,透光率下降了11.90%；氧气阻隔性能良好,氧气透过系数为1.771±0.196×10_-12 ^cm₃^.cm/(cm₂^.s.Pa),在环保包装、食品保鲜等领域具有广阔的应用前景。     

Preparation and performance of PANI–PVA composite film doped with HCl

The polyaniline (PANI)–poly (vinyl alcohol) (PVA) composite film doped with HCl was prepared by adopting PVA as matrix. Effects of PVA content and film drying temperature on properties of HCl–PANI–PVA composite film were studied. A comparison was made for tensile strength, elasticity, conductivity and thermal stability of PVA, HCl–PANI or HCl–PANI–PVA. PVA film presented the highest tensile strength and elasticity (150.8?MPa and 300.0%), but its conductivity was the lowest. The conductivity of HCl–PANI–PVA was the highest (1500?S?m^?1), and tensile strength and elasticity of HCl–PANI–PVA were higher than those of HCl–PANI. The order of their thermal stability is PVA?>?HCl–PANI?>?HCl–PANI–PVA before 260°C, and the order of their thermal stability is HCl–PANI?>?HCl–PANI–PVA?>?PVA after 260°C. At the same time, the structure and conductive mechanism of composite materials were characterised and analysed through infrared and scanning electron microscopy (SEM).     

Multifunctional and pH-responsive dialdehyde cellulose/polyvinyl alcohol composite film reinforced with curcumin

The rational design of food packaging films with good antimicrobial activity, antioxidant activity, and monitorability is of great importance in intelligent packaging. In this study, an active composite film was prepared by adding curcumin to a dialdehyde cellulose (DAC)/polyvinyl alcohol (PVA) matrix. It was found that the Cur/DAC/PVA composite film exhibited optimal tensile strength at 30°C. The tensile strength of the composite film control PVA/DAC film was observed to increase by 176% due to the affection of hydrogen bonding. Under the influence of curcumin, the UV barrier property and antioxidant activity of the composite film were significantly increased, and the ABTS⁺• was removed by 0.5Cur/DAC/PVA up to 88% at low curcumin content. The water solubility and water vapor permeability were both reduced to some degree. It was also observed that composite film displayed an inhibitory effect on the growth of Staphylococcus aureus bacteria. Meanwhile, the Ritger and Peppas release model was used to study the release control capability of curcumin. Furthermore, the Cur/DAC/PVA composite film demonstrated excellent color response to pH, which it they could be used for intelligent packaging with real-time visual monitoring.     

Preparation of PANI–PVA composite film with good conductivity and strong mechanical property

The polyaniline (PANI)–polyvinyl alcohol (PVA) conductive composite films [doped with hydrochloride (HCl), dodecylbenzene sulphonic acid and amino sulphonic acid (NH₂SO₃H) aqueous solution] were synthesised by ‘in situ’ polymerisation, and their conductivities were compared. Among these composite films, HCl–PANI–PVA composite film possessed the highest conductivity that reached 1360?S·m^??1 [w_(PVA)?=?40%]. Meanwhile, the effects of PVA content, HCl concentration, oxidant ammonium persulphate (APS) dosage, reaction time and film drying temperature on tensile strength of the HCl–PANI–PVA composite films were studied. The tensile strength of the film was improved greatly due to effective mixture of PANI and PVA. When the PVA content was 40%, C_(HCl)?=?1.0?mol·L^??1, reaction time was 4.0?h, n_(APS)/n_(aniline)?=?1.0 and film drying temperature was 80°C, and the tensile strength of the HCl–PANI–PVA composite film reached the maximum of 60.8?MPa. At the same time, the structure of composite materials was characterised and analysed through ultraviolet spectrum and SEM.     

Preparation of hydroxyapatite/poly(vinyl alcohol) composite film with uniformly dispersed hydroxyapatite particles using citric acid

Biocompatible hydroxyapatite (HA)/poly(vinyl alcohol) (PVA) composites and their transparent films were prepared by the coprecipitation and solvent casting method. The formation of HA in PVA composite powder was confirmed by the characteristic phosphate bands at 1100–1032 and 565 cm^?1 at FT‐IR spectra, and the weight ratio of HA to PVA was 50/50 examined by TGA. The crystal melting temperature of HA/PVA decreased compared with that of pure PVA. HA/PVA (50/50) composite powder and pure PVA were dissolved in dimethyl sulfoxide to obtain a film with HA/PVA weight ratio of 10/90. To improve HA particles' dispersity, which is one of the major factors affecting the mechanical properties of composite materials, various contents of citric acid were used for the preparation of HA/PVA films. At a citric acid concentration of 5 wt %, HA/PVA film with good dispersity of HA particles was obtained. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

复合聚电解质凝胶的制备与性能研究 Ⅰ.表面性能对凝胶的影响

采用柱状灯芯技术(Column Wicking Technique)研究了三种不同阳离子的木质素磺酸盐(木质素磺酸钠、钙和镁)的表面性能,同时应用电导率测试法对聚丙烯酰胺(PAAM)/木质素磺酸盐聚电解质凝胶的形成过程进行了研究。结果表明:木质素磺酸钙具有最高的表面能,而木质素磺酸钠的表面能最低。结合对凝胶过程的研究进一步发现,相对于聚丙烯酰胺凝胶来说,加入木质素磺酸盐对聚电解质凝胶的体系的影响是非常明显的,即木质素磺酸盐表面能大,则所形成的凝胶的电导率就小。上述结论也在实验过程得到了验证,根据手感可发现,在三种木质素磺酸盐中,加入木质素磺酸钙所形成的聚电解质凝胶具有较好的致密性和较高的强度。