Miscibility of Poly(hydroxybutyrate)/Poly(vinyl alcohol)Melt Blends Plasticized With Glycerol

Poly(hydroxybutyrate)/poly(vinyl alcohol)(PHB/PVA)blends plasticized with glycerol were prepared by melt blending of PHB and glycerol plasticized PVA.The PHB/PVA-glycerol compositions were 90:10,75:25 and 50:50 w/w,being the concentration of glycerol in the PVA mixture of 10 wt%.The blends were characterized by infrared spectroscopy,dynamic-mechanical thermal analysis,and scanning electron microscope of the fragile fractured surface.The results showed one single phase blend,indicating miscibility corroborated by the presence of a single glass transition temperature.The blending method proved to be an efficient way to tune PHB properties keeping its biodegradable nature since both PVA and glycerol are fully biodegradable materials.

Compatibility and Properties of Biodegradable Blend Films with Gelatin and Poly(vinyl alcohol)

The blend films with gelatin and poly（vinyl alcohol） （PVA） were prepared by a solution casting method. The compatibility between gelatin and PVA in the blend films was investigated. The transmittance, Fourier-transform infrared spectroscopy （FTIR）, x-ray diffraction （XRD）, thermogravimetry analysis （TG）, and differential scanning calorimetry （DSC） were employed to characterize the resultant blend films. According to optic result, the opacity of the blend film at the ratio of 20/80 （w/w, Gel to PVA） was the lowest, indicating the best compatibility between Gel and PVA at the ratio. The results oflR, XRD, DSC, and TG revealed an intensive interaction and good compatibility between them in the blend film at the ratio. The mechanical properties and solubility showed that PVA content in the blend films obviously affected the elongation at break and solubility. The mechanical properties and water resistance of gelatin film may be improved by the introduetion of PVA.

PHASE SEPARATION AND MICROVOID FORMATION AT PHASE INTERFACES OF HYDROPHOBIC-HYDROPHILIC POLYMER BLENDS DURING WET PROCESSING

In this paper,morphological structure,thermodynamic compatibility and relationship be-tween porosities and blend ratios of the wet coagulated PU/PVA sheets were studied by meansof observation of scanning electronic micrographies,tests of dynamic mechanical properties,moisture regain and vapor permeability.Furthermore,the formation of microvoids at interfacesof separated phases was discussed and a microvoid formation mechanism at phase interfaces ofhydrophobic-hydrophilic blends was suggested and compared with that ofhydrophobic-hydrophobic blends.

PVDF/PVA共混膜的制备及其在去除污水COD中的应用

以聚乙烯醇(PVA)、聚偏氟乙烯(PVDF)为原料,聚乙烯吡咯烷酮为溶剂,制备了PVDF/PVA共混膜。将该膜应用于膜生物反应器处理污水,测试化学需氧量(COD)去除率和膜的使用性能。结果表明:膜的水通量随PVA加入量的增加而逐渐增加,在牵伸比为1.7时,膜的水通量达到最大值;平板膜用清水清洗后,膜的水通量恢复率较高,膜的运行周期经第一次清洗后下降了18 h,经第二次和第三次清洗后,膜的运行周期基本稳定在6~8 h,COD去除率高于90%,表明该膜具有良好的使用性能。

聚丙烯腈对聚乙烯醇膜形貌和性能的改进

通过流延成膜的方法制备了聚乙烯醇/聚丙烯腈共混薄膜。通过扫描电镜分析了共混膜的形貌。通过差式扫描量热仪、热重分析、拉伸测试、表面接触角测试研究了共混膜的热力学性能、机械性能和化学性能。测试结果显示聚丙烯腈对聚乙烯醇膜的形貌和性能产生了显著的影响。

木质素基水性聚氨酯/聚乙烯醇共混膜制备及性能

环境友好型薄膜代替传统石油基薄膜用于农用地膜等领域愈发引起广泛的关注和研究。薄膜性能的提高仍然是当下所要攻克的难题。针对解决传统聚乙烯醇(polyvinyl alcohol,PVA)在薄膜领域力学强度低,耐水性及隔绝紫外能力差的缺点,同时为了能够更好的提高生物质资源的使用价值,该研究以聚乙烯醇(PVA)为原料,木质素(Lignin)、水性聚氨酯(waterborne polyurethane,WBPU)作为填料剂,对木质素进行液化制备木质素液化物L(D),采用溶液浇筑法成功制备木质素基水性聚氨酯/聚乙烯醇共混膜。通过对共混膜的光学性能,形貌特征,化学结构和晶体结构进行表征分析,探究了木质素用量,L(D)/WBPU质量比对共混膜的影响。结果表明,L(D)与WBPU均能与PVA充分混合,并在含有15%L(D)的共混膜中表现出的力学性能和耐水性能最好,拉伸强度提升了10%,耐水性提高了32%,同时加强了膜的抗紫外能力,在400 nm紫外区的透光率从81.44%降低至7.69%;在不同L(D)/WBPU质量比的作用下,膜的耐水性和抗紫外性都得到进一步的加强,耐水性最高提升了68%,400 nm紫外区的透光率接近于0。该研究制备的共混膜具备较高的应用潜力,同时对食品、医药包装等领域有一定的参考意义。

共聚焦拉曼成像技术研究PE⁃LD/EVOH共混物的三维相结构

利用共聚焦拉曼成像技术研究了低密度聚乙烯(PE⁃LD)/乙烯⁃乙烯醇共聚物(EVOH)共混物中各相在压塑样品水平方向、深度方向和三维空间的分布情况,首次获得了PE⁃LD/EVOH共混物的三维相结构,并直观地将相区与共混物化学成分相对应。结果表明,PE⁃LD/EVOH共混物为不相容体系;当EVOH的质量分数为20%时,其作为分散相,以较规则的圆柱体形态分散于PE⁃LD基体中,圆柱直径尺寸在3~6μm范围内。加入马来酸酐接枝聚乙烯(PE⁃g⁃MAH)作为相容剂后,共混物的相态结构发生显著变化,分散相形状由规则变为不规则,截面的平均尺寸减小到约2μm,这说明PE⁃g⁃MAH可显著增强PE⁃LD与EVOH两组分间的界面相容性。

耐酒精专用胶料的研制

以三元乙丙橡胶(EPDM)和异戊橡胶(IR)为主体材料,研究填料体系、硫化体系和生胶体系对硫化胶物理性能、耐酒精性能和安全性能的影响。结果表明:以EPDM(牌号5470C)单用、二氧化硅VN3/925粉并用和采用硫化剂双25硫化体系的硫化胶具有良好的物理性能、耐酒精性能和安全性能,气味可以达到德国食品接触材料法规LFGB的二级指标要求,但胶料的加工性能和硫化胶的气密性较差;EPDM/IR硫化胶具有良好的气密性、物理性能和耐酒精性能,经二次硫化和水煮后不喷霜,气味可以达到LFGB的二级指标要求,安全性能好,综合性能优异。耐酒精专用胶料适合采用EPDM/IR并用。

复配醇胺捕集CO_(2)的微波解吸工艺研究

针对传统醇胺法捕集CO_(2)工艺需要高温(100℃以上)解吸的问题,从优化醇胺吸收液组成和优化解吸工艺两方面着手进行工艺优化,在优化CO_(2)吸收条件的基础上提出了一种高效的微波加热解吸CO_(2)方法,并优化了CO_(2)醇胺吸收液的微波加热解吸工艺。结果表明:复配醇胺优选由N-甲基二乙醇胺(MDEA)、哌嗪(PZ)、羟基乙二胺(AEEA)组成,当MDEA、PZ和AEEA的质量比为3∶1∶5时,复配醇胺的水溶液吸收CO_(2)的效果最佳;以复配醇胺质量分数为20%的水溶液作为CO_(2)吸收液,30℃下的CO_(2)平衡吸收容量为1.15 mol/mol;利用微波加热,在95℃下解吸4 min时即可达到解吸平衡,CO_(2)的解吸率达97.52%,基本实现全部解吸。与传统的加热解吸方法相比,相同温度下微波加热法的CO_(2)解吸率提高62.25百分点,而且解吸时间显著缩短,实现了CO_(2)低温高效解吸。

大豆蛋白/聚乙烯醇共混膜的性能研究

以大豆蛋白(SPI)和聚乙烯醇1788(PVA)作为主要的成膜物质,制备了共混薄膜,研究了丙三醇及聚乙烯醇的用量对薄膜的物理性能的影响,采用红外光谱仪对共混膜的结构进行了表征。结果表明,丙三醇和PVA的用量对共混物的成膜能力及力学性能具有重要影响。丙三醇用量太少时,体系不能成膜;随着丙三醇的用量增加,共混膜的拉伸强度存在极值,断裂伸长率则在丙三醇用量大于3.0g后有显著上升。当PVA用量分别为30%和40%时,不能得到完整的薄膜;随着PVA的用量增加,复合膜的拉伸强度和断裂伸长率均略有下降,用量达到50%后,两者均出现急剧上升,在90%时达到极大值。随着PVA的用量增加,膜的吸水率表现出下降、上升、下降的变化规律。PVA用量小于20%时,共混膜的析出率的变化不明显,超过20%后,析出率出现急剧下降,大于50%后又有明显上升。随着PVA的用量增加,高波数的羰基的红外振动峰出现并逐渐变大,低波数的羰基峰则逐渐减小,两者的波数均逐渐增大。

Study on PVA Membranes Blended with Acrylic Ester-Acrylic Acid Copolymer for Dehydration of Ethanol

The viability of polyvinyl acetate (PVA) membranes blended with acrylic ester-co-acrylic acid copolymers (AE-co-AA), for ethanol dehydration was examined. The effects of the operating temperature on the permeate flux and separation factor of the membranes were investigated. The pervaporation separation characteristics of PVA/(AE-co-AA) membranes were related to the blend ratio, the dose of crosslinking agents and the operating temperature.

Zingiber cassumunar blended patches for skin application:Formulation,physicochemical properties,and in vitro studies

Our work was to study the preparation,physicochemical characterization,and in vitro characteristic of Zingiber cassumunar blended patches.The Z.cassumunar blended patches incorporating Z.cassumunar Roxb.also known as Plai were prepared from chitosan and polyvinyl alcohol with glycerin as plasticizer.They were prepared by adding all ingredients in a beaker and homogeneously mixing them.Then,they were transferred into Petri-dish and dried in hot air oven.The hydrophilic nature of the Z.cassumunar blended patches was confirmed by the moisture uptake,swelling ratio,erosion,and porosity values.The FTIR,DSC,XRD,and SEM studies showed revealed blended patches with amorphous region that was homogeneously smooth and compact in both surface and cross section dimensions.They exhibited controlled the release behavior of(E)-4-(30,40-dimethoxyphenyl)but-3-en-lol(compound D)that is the main active compound in Z.cassumunar for anti-inflammation activity.However,in in vitro skin permeation study,the compound D was accumulated in newborn pig skin more than in the receptor medium.Thus,the blended patches showed the suitable entrapment and controlled release of compound D.Accordingly,we have demonstrated that such chitosan and polyvinyl alcohol formulated patches might be developed for medical use.

Fabrication of Chitosan/Poly (vinyl alcohol) Porous Membrane for Wound Dressing

A porous,biocompatible,and modifiable chitosan (CS)/poly (vinyl alcohol) (PVA) hybrid membrane, which can be evaluated as wound dressing,has been prepared by lyophilization method and using the low toxicity solvents. Experiments illustrated that the moisture regain and porosity rate of polymer blend membranes had the similar variation tendency and got the maximum value at the case of CS/PVA weight ratio of 6∶4. And the value of water vapor transmission rate( WVTR) is conductive to the healing of wound and desirable for the application as a wound dressing.Mechanical performance test of blend membrane showed that the presence of PVA could effectively improve the interaction between CS molecules. The scanning electron microscopy( SEM)photograph confirmed the porous surface on top-layer supported by a macroporous sponge-like sub-layer of this novel type of CS blend membrane. Besides, Fourier transform infrared spectroscopy( FTIR) revealed the facts that the two polymers were physically bended and certain chemical actions took place,which illustrated the good compatibility between them. Differential scanning calorimetry(DSC) results showed that decomposition reaction occurred in CS at about 210℃. Introducing of PVA to CS made the decomposition temperature of blend membrane decrease. The good properties,such as moisture regain,porosity rate,and WVTR,of this kind of CS/PVA blend membranes suggested a potential application as a wound dressing in the future.

Modified PVA-CA blend ultrafiltration membrane by alkali metal chloride

The modified PVA CA blend ultrafiltration membranes were prepared by phase inversion from the casting solutions consisting of polyvinyl alcohol(PVA), cellulose acetate(CA), acetic acid, alkali metal chloride and water. The effects of different concentration of alkali metal chloride on the properties of membranes were investigated. The results show that when the mass fraction of the salt in the casting solution is not greater than 1%, the property of rejection of the alkali metal salt modified ultrafiltration PVA CA blend membrane has little change compared with that of the unmodified PVA CA blend membrane, but the permeation flux is much greater than that of the unmodified membrane under the same operation condition. When the mass fraction of the salt is greater than 1.5%, the permeate flux increases much greater than that of the unmodified membrane, but the property of rejection of the modified ultrafiltration membrane decreases greatly. The results also show that the contact angle of the salt modified PVA CA blend UF membrane decreases but the swelling in water increases with the increment of the mass fraction of alkali metal salts. Furthermore, the NaCl modified PVA CA blend membrane has a slightly lower swelling and a little smaller contact angle of water than the KCl modified PVA CA blend membrane does when the mass fraction of salts is the same.

高氧气阻隔性聚乙醇酸/乙烯-乙烯醇共聚物共混物的制备及性能

通过熔融挤出方法制备了聚乙醇酸(PGA)/乙烯-乙烯醇共聚物(EVOH)共混物及其膜,利用DSC,SAXS/WAXS等方法,研究了PGA含量对共混粒子结晶性能及共混物膜性能的影响。实验结果表明,PGA与EVOH有较好的相容性,PGA/EVOH共混物只有一个玻璃化转变温度(Tg),当以EVOH为主相时,少量PGA的加入可破坏EVOH分子堆砌紧密程度,使其Tg降低,促进PGA/EVOH共混物膜中的EVOH结晶。当以PGA为主相时,EVOH起成核剂作用,使PGA的熔点升高,结晶完善。当PGA含量为5%(w)时,共混物膜的氧气阻隔性较EVOH膜有所提高。当PGA含量(w)在10%~20%时,共混物膜的拉伸强度随PGA含量的增加而增大。当PGA含量为20%(w)时,共混物膜的断裂伸长率显著增加至45%。

聚乳酸/塑化聚乙烯醇合金开孔发泡行为研究

以聚乳酸(PLA)为基体,加入不同含量的塑化聚乙烯醇(CPVA),通过熔融共混法制备PLA/CPVA合金样品。以超临界CO_(2)为物理发泡剂,采用釜压发泡和粒子沥滤法成功制备出PLA/CPVA合金开孔泡沫。结果表明,随着CPVA含量的增加,PLA的结晶温度下降,结晶度先上升后下降,熔体黏弹性改善;随着CPVA含量的上升,PLA/CPVA合金开孔泡沫的发泡倍率先减小后逐渐增大,开孔率逐步提高;当CPVA含量为50%(质量分数,下同)时,PLA/CPVA合金开孔泡沫的发泡倍率为23.1倍,开孔率达到了91.6%。

聚乙烯醇/紫胶树脂膜的制备及性能初探

聚乙烯醇(PVA)与紫胶树脂(SLR)均为易成膜树脂,且二者主要作为膜制品来应用。为改善SLR成膜后水汽渗透性差、脆性高等特性,特增加PVA,且分别以ω(PVA)为0%、10%、20%、30%、40%、50%时与SLR进行水相共混成膜,着重研究了二者成膜的可行性并确定了其成膜工艺:分别制备SLR水乳液和PVA水溶液,并将二者于50℃条件混合均匀,最后将液体倒入培养皿中,干燥、成膜。对成膜样品分别进行了表面形态观测、水静滴接触角分析、吸湿性测定,结果表明:PVA和SLR具有一定的物理相容性,PVA的加入提高了SLR膜的致密性,且随着PVA含量的增加,PVA/SLR膜的致密性增加,二者发生化学反应的程度较低;PVA质量分数最高时[本研究中ω(PVA)为50%]的PVA/SLR膜亲水性最强、吸湿性最大,表明PVA的加入改善了SLR的亲水性,且PVA的加入量越大,膜的亲水性、吸湿性增加的程度越大。

Synthesis of tetrahedrally coordinated CoO for higher alcohol synthesis directly from syngas

Higher alcohol synthesis directly from syngas is highly desirable as one of the efficient non-petroleum energy conversion routes.Co^(0)–CoO catalysts showed great potential for this reaction,but the alcohol selectivity still needs to be improved and the crystal structure effect of Co^(0)on catalytic behaviors lacks investigation.Here,a series of tetrahedrally coordinated Co^(0)polymorphs were prepared by a thermal decomposition method,which consisted of wurtzite CoO and zinc blende CoO with varied contents.After diluting with SiO_(2),the catalyst showed excellent performance for higher alcohol synthesis with ROH selectivity of 45.8%and higher alcohol distribution of 84.1 wt%under the CO conversion of 38.0%.With increasing the content of wurtzite CoO,the Co^(0)/Co^(2+)ratio gradually increased in the spent catalysts,while the proportion of highly active hexagonal close packed cobalt in Co^(0)decreased,leading to first decreased then increased CO conversion.Moreover,the higher content of zinc blende CoO in fresh catalyst facilitated the retention of more Co^(2+)sites in spent catalysts,promoting the ROH selectivity but slightly decreasing the distribution of higher alcohols.The catalyst with 40%wurtzite CoO obtained the optimal performance with a space time yield toward higher alcohols of 7.9 mmol·gcat^(-1)·h^(-1).

全自动蒸馏-甘油浴法测定配制酒中的氰化物

将全自动蒸馏与甘油加热方式相结合,建立了一种快速测定配制酒中氰化物含量的方法。研究蒸馏过程中的功率、加水量、吸收液的浓度、蒸馏时间、去除高沸点有机物的加热方式和温度对配制酒中氰化物测定的影响,并与国家标准方法GB 5009.36—2016第一法进行比对,对百香果配制酒、鹿鞭酒、人参酒3种样品中的氰化物含量进行检测分析。结果表明,全自动蒸馏-甘油浴法的回收率为82.4%~85.7%,标准偏差为2.6%~3.2%,国标方法回收率为70.9%~81.8%,标准偏差为10.8%~13.9%。与国家标准方法相比,该方法所使用的时间较短,步骤简单,结果测定准确可靠,可实现配制酒的高通量准确检测。

甲基玉米淀粉/PVA可降解薄膜的研制

研究了以甲基玉米淀粉和PVA为原料共混制备可降解薄膜的关键参数。通过方差分析发现淀粉甲基化对薄膜的拉伸强度(σ)和断裂伸长率(δ)有显著影响(P<0.05),对透光率(T)和吸水率(W)有极显著影响(P<0.01);通过DPS软件系统对数据进行非线性拟合得出相关数学模型,表明甲基淀粉取代度(DS)、甲基淀粉含量、甲醛用量、甘油用量、尿素用量等各因子间存在明显交互作用,随甲基淀粉取代度的提高,薄膜拉伸强度、透光率均有所增加,薄膜相容性好,吸水率下降,即耐水性提高。