石墨烯微片/天然橡胶纳米复合材料的研究

目的 研究石墨烯微片的添量对石墨烯微片/天然橡胶纳米复合材料性能的影响,并对机械共混法和胶乳共混法进行比较。方法 探索复合材料的制备工艺,利用扫描电镜(SEM)、透射电镜(TEM)、拉曼光谱(RDS)、万能力学试验机等对石墨烯微片和石墨烯微片/天然橡胶纳米复合材料的形貌、结构以及性能进行分析和研究。结果 测试结果表明,石墨烯微片作为填料添加到复合材料中,使复合材料的性能得到了增强。相比纯橡胶而言,石墨烯微片(10 phr)/天然橡胶复合材料的拉伸强度增加了41.5%,热导率增加了153.3%。结论 石墨烯微片可以大幅度提高复合材料的性能,并且胶乳共混法制备的复合材料的性能要优于机械共混法制备的复合材料的性能。     

温度对核壳胶乳涂膜形成及性能的影响

研究了温度对P(St-co-BA)/P(BA-co-MMA)核壳型复合胶乳的成膜及其性能的影响.通过涂膜干燥速率由线、透光率、吸水率及水蒸汽渗透系数随温度的变化,发现在40℃～90℃内适宜的温度下,可加速膜的形成、提高涂膜的性能.而当在临界温度(90℃)以上成膜或退火时,可使胶膜产生二次相分离,且在膜内产生微裂纹、针孔及空穴等缺陷,但这些针孔不是贯通的.     

Preparation and Characterization of the Modified Polyvinylidene Fluoride （PVDF） Hollow Fibre Microfiltration Membrane

A novel thermally induced graft polymerization technique was used to modify a polyvinylidene fluoride （PVDF） hollow fibre microfiltration membrane. An artificial neural network （ANN） was applied to optimize the prepared condition of the membrane. The optimized dosing of acrylic acid （AA）, acrylamide （AM）, N, N＇- methylenebisacrylamide （NMBA） and potassium persulphate （KSP） designed by ANN was that AA was 40.63 ml/L; AM acted as 6.25 g/L; NMBA was 1.72 g/L and KSP was 1.5 g/L, respectively. The thermal stability of the PVDF modified hollow fibre membrane （PVDF-PAA） was investigated by thermogravimetric （TG） and differential scanning calorimetry （DSC） analysis. The polycrystallinity of the PVDF-PAA membrane was evaluated by X-ray diffraction （XRD） analysis. The complex formation of the modified membrane was ascertained by Fourier transform infrared spectroscopy （FTIR）. The morphology of the PVDF-PAA membrane was studied by environmental scanning electron microscopy （ESEM）. The surface compositions of the membrane were analyzed by X-ray photoelectron spectroscopy （XPS）. The adsorption capacity of Cu^2＋ ion on the PVDF-PAA hollow fibre membrane was also investigated.     

Ultrasensitive Detection of Prostate‐Specific Antigen and Thrombin Based on Gold‐Upconversion Nanoparticle Assembled Pyramids

Self‐assembled nanostructures have been used for the detection of numerous cancer biomarkers. In this study, a gold‐upconversion‐nanoparticle (Au‐UCNP) pyramid based on aptamers is fabricated to simultaneously detect thrombin and prostate‐specific antigen (PSA) using surface‐enhanced Raman scattering (SERS) and fluorescence, respectively. The higher the concentration of thrombin, the lower the intensity of SERS. PSA connected with the PSA aptamer leads to an increase in fluorescence intensity. The limit of detection of thrombin and PSA reaches 57 × 10^?18 and 0.032 × 10^?18m , respectively. In addition, the pyramid also exhibits great target specificity. The results of human serum target detection demonstrate that the Au‐UCNP pyramid is an excellent choice for the quantitative determination of cancer biomarkers, and is feasible for the early diagnosis of cancer.     

Enzyme immobilization in latex dispersion coatings for active food packaging

Carboxylated styrene acrylate latex samples have been functionalized by the immobilization and entrapment of the enzyme glucose oxidase (GOx), which can be used as an oxygen scavenger in food packaging. GOx was covalently immobilized both on the surface of already formed films and on the latex particles in dispersion, as well as entrapped within the polymer matrix. In the latter two cases, polymer films were formed after the enzyme had been added to the latex dispersion. The storage stability of the enzyme and the influence of adding clay were also studied. For a given amount of enzyme, the enzyme immobilized on the film surface showed an enzyme activity about 10 times higher than that of the enzyme present within the polymer matrix. This is probably due to the diffusion limitations of the substrate in the polymer matrix. The films with the enzyme present within the polymer matrix, however, showed a higher total oxygen‐removal capacity than films with the enzyme immobilized on the surface. Entrapped enzyme showed a slightly higher activity than enzyme immobilized in the dispersion due to the negative effect of the activating chemicals used during the immobilization and on conformational constraints upon covalent bonding. Low amounts of clay added to the dispersion decreased the enzyme activity, but with higher amounts of clay the enzyme activity increased, probably because of the increased porosity and thus higher substrate accessibility. The most suitable storage condition for all the enzyme‐containing films was +8°C, which is just above the glass transition temperature of the polymer used. Copyright © 2007 John Wiley & Sons, Ltd.     

核-壳型聚合物乳液对照像性能的促进和稳定作用

人工合成聚合物被广泛应用于卤化银感光材料,改善其物理力学性能。经过试验发现,特殊设计,合成的核－壳型聚合物乳液用于 化银感光材料涂层中,不仅能提高胶片的物理力学性能,对照像性能也能产生促进和稳定作用;在胶片的人工老化过程中,对照像性能,尤其是反差和感光度的衰退起到明显的抑制作用,特别适用于高感、高反差印刷制版胶片。在大量应用试验的基础上,对其作用机理作了有益的探讨。     

丙烯酸正十二酯的合成

以丙烯酸和正十二醇为原料,在硫酸催化剂作用下制备了丙烯酸正十二酯。用正交试验设计法研究了原料配比、催化剂用量、阻聚剂和携水剂的种类及其用量、反应温度、反应时间对酯化反应的影响。经理化测定和红外光谱分析证实,所得结果与文献报道的结果相符。     

用种子半连续法制备微米级PS乳胶粒

用种子半连续乳液聚合法,用油溶性氧化剂和水溶性还原剂引发剂体系,辅导以水相阻聚剂合成了粒径大于０．８μｍ的单分散ＰＳ乳胶粒。在种子乳液中适量加入过氧化物,有利于提高种子半连续乳液聚合的转化率,使用交联的种子才能较好地进行种子半连续聚合。     

松香树脂的乳化及与天然胶乳的复合稳定性

以权香酸皂为乳化剂，对松香树胆的乳化条件进行了探讨，考察了松香树脂乳液的稳定性，并将稳定的松香树脂液公不同比例与天然胶乳混合，研究其复合稳定性，结果表明，混合时入适量的ＴＸ－１０，可在较宽的配比范围内得到稳定的复合乳液，为水乳型橡胶压敏胶的生产提供了基本条件。     

辐射引发种子乳液聚合制备硅氧烷/丙烯酸酯共聚乳液

采用^60Co γ-ray辐射引发种子乳液聚合法合成了聚有机硅氧烷(PSI)／丙烯酸酯共聚物乳液。通过TEM和IR分析对复合粒子微观形态和产物结构进行了表征,同时对乳胶膜的力学性能做了研究。结果表明,通过辐射引发PSI种子乳液聚合,制得了具有核壳式结构的P(SI—BA—MMA)共聚乳胶粒子。随着PSI含量的增加,复合乳胶膜的力学性能显著增强。