Polyvinyl Acetate as a High-gloss Edible Coating

Edible coating formulations were made with food-grade polyvinyl acetate (PVA) dissolved in alcohol-water mixtures. PVA coatings had high gloss and relatively high permeance to O₂ and water vapor, and they formed glossy surfaces on chocolate candy, citrus fruit, and apples. Addition of propylene glycol helped to retain coating gloss when the alcohol content of the solvent was reduced to less than 70%. Fresh apples or citrus fruit with PVA coatings had higher internal O₂ than fruit with shellac and resin coatings and, consequently, less tendency to ferment and produce alcohol during storage. Fruit with PVA coatings did not whiten or ‘blush’ after contact with water.     

液相还原法制取纳米银粉的研究

以硝酸银为原料,水为反应介质,聚乙烯吡咯烷酮为保护剂,甲酸铵作为还原剂,利用普通液相还原法常温一步直接制备得到平均粒径在10nm左右的纳米级银粉。采用XRD、EDS、TEM等测试手段,对所制得的纳米银粉进行了表征。并简要讨论了纳米银粉制备过程中的各类影响因素。     

亚甲基蓝掺杂聚乙烯醇四波混频的实验研究

为了研究在低功率连续He-Ne激光条件下亚甲基蓝掺杂聚乙烯醇薄膜简并四波混频的基本特性,采用简并四波混频技术研究了亚甲基蓝掺杂聚乙烯醇的相位共轭光与入射角度、前抽运光和后抽运光的变化关系,以及透射光栅和反射光栅对相位共轭光的影响.在实验中得到了最大的相位共轭反射率为0.27%.所得的结果对研究染料固化在固体基质中的非线性研究是有帮助的.     

Si基SiC微通道及其制备工艺

提出了一种用于MEMS的硅基SiC微通道(阵列)及其制备方法,它涉及半导体工艺加工硅晶片和化学气相淀积方法制备SiC。在Si(100)衬底上用半导体工艺刻蚀出凹槽微结构,凹槽之间留出台面,凹槽和台面的几何尺寸(深度、宽度、长度)及其分布方式根据需要而定,此凹槽微结构用作制备SiC微通道的模板;用化学气相淀积方法在模板上制备一厚层SiC材料,此层SiC不仅完全覆盖衬底表面的微结构包括凹槽和台面,还在凹槽顶部形成封闭结构,这样就在衬底上形成了以凹槽为模板的SiC微通道(阵列)。对淀积速率与微通道质量之间的关系进行初步分析,发现单纯地提高淀积速率不利于获得高质量的微通道。     

玻璃纤维增强TPVA/PBST复合材料的制备及性能

研究了短玻璃纤维(SGF)增强热塑性聚乙烯醇(TPVA)/聚丁二酸对苯二甲酸丁二醇酯(PBST)复合材料的改性机理、复合材料的热学及力学性能,并对复合材料中玻璃纤维(GF)的尺寸及分布进行了分析.实验结果表明,马来酸酐接枝乙烯-乙酸乙烯酯共聚物(EVA-g-MAH)与硅烷偶联剂能够有效增容TPVA/PBST复合材料,引...     

碳中和目标背景下包装行业发展的对策

目的 为了应对日益恶化的全球气候变化,并实现碳中和的目标,研究低碳化技术在包装行业的应用成为当下至关重要的任务。为了推动包装行业在碳中和背景下的低碳化转型,有必要对现有的低碳化技术进行分类和梳理。方法 从碳减排和碳移除两方面对包装行业已有的低碳化技术进行了研究。综述当前可降解生物塑料和聚合物单体化学循环技术在包装中的应用,介绍了几种清洁能源以及碳捕捉、碳利用和碳储存技术的发展现状。结论 对包装行业而言,实现碳中和的目标还面临着很多挑战。包装行业在推进碳中和目标时要选取与发展适合的低碳能源和碳中和技术。     

Stabilizing effect of the cyclodextrins additive to spray-dried particles of curcumin/polyvinylpyrrolidone on the supersaturated state of curcumin

Although curcumin is considered to have various therapeutic effects, its use as a functional food or supplement is restricted owing to its low water solubility and bioavailability. To increase the solubility of curcumin in water, the use of polyvinylpyrrolidone (PVP) and vinylpyrrolidone-vinyl acetate copolymers with a pyrrolidone skeleton was noted to be promising. In particular, the bi-component formulations of curcumin/PVP prepared through spray drying exhibited an amorphous state in powder X-ray diffraction observations and temporally increased the apparent solubility of curcumin to over 5000 times that of untreated curcumin; nevertheless, after 24 h, the solubility decreased owing to the unstable supersaturated state of curcumin. The addition of α-cyclodextrin (α-CyD) in the bi-component curcumin/PVP formulation helped maintain the supersaturated state of curcumin, whereas the addition of β- and γ-CyD led to the collapse of the supersaturated state. The addition of α-CyD can likely help inhibit the nucleation and crystal growth of curcumin, through the interaction among the solubilized units of curcumin/PVP and α-CyD.     

影响PVC塑窗耐候性的因素及防止老化的措施

分析影响聚氯乙烯(PVC)塑窗耐候性的内因和外因,指出内因是PVC分子结构中出现的不规则连接、不饱和双键、支链等,外因主要是环境因素,即光、热、氧产生的老化,以及湿度的影响,并从冲击改性剂、稳定剂、着色剂、紫外线吸收剂及抗氧剂的选择方面提出了防止PVC塑窗老化的措施。     

Nylon—6含油废水除油并回收单体的实验研究

本文介绍了Ｎｙｌｏｎ－６含油乳化废水破乳除油并回收单体的方法。     

聚氯乙烯树脂热稳定性探讨

通过对聚氯乙烯降解机理的分析,提出在聚合体系中添加助剂并控制单体质量,改进工艺措施,提高PVC树脂制品的热稳定性。