聚乙烯醇共混改性膜作为农药种衣剂成膜剂的性能研究

以水溶性聚合物聚乙烯醇(PVA)和水不溶性聚合物乙酸乙烯-乙烯共聚物(VAE)乳液为原料,采用溶液共混法制备了PVA-VAE共混膜,为农药成膜剂的制备开辟了新途径。红外光谱、透射电镜、激光粒度仪测试结果显示,PVA溶液中的胶束被打开,体系的比表面积急剧增大,两相间的界面消失,说明共混体系分子间具有良好的相容性;透水性与耐水性测定结果表明,PVA-VAE的质量比为80∶ 20、70∶ 30、60∶ 40时其共混膜的性能适用于农药种衣剂的成膜剂;种子发芽试验显示,与单独使用PVA膜相比,引入适当比例VAE后的共混膜用于种子包衣,其耐水性显著提高,渗水率适宜,对种子发芽无明显影响。     

甲醛交联碱木质素-聚乙烯醇-尿素薄膜氮元素缓释性能研究

采用交联法制备了碱木质素-聚乙烯醇-尿素-甲醛(AL-PVA-U-F)交联薄膜,分析碱木质素(AL)和交联剂甲醛(F)的加入量对氮元素缓释的影响,研究薄膜对氮元素的缓释机理,并采用XRD和FT-IR-ATR方法分析薄膜的结晶度和化学结构,结果显示碱木质素的加入可降低薄膜中氮元素的缓释速率,使氮元素达到释放平衡的时间增大,碱木质素和聚乙烯醇质量比5∶5时复合薄膜192 h时达到释放平衡,释放平衡时间最长,氮元素累积释放率最大为77.73%。加入适量的甲醛交联剂使碱木质素、聚乙烯醇、尿素、甲醛之间发生化学反应,线性和网状结构交互从而使薄膜中氮元素缓释减慢。与共混薄膜(ALPVA-U)相比,甲醛的交联作用使薄膜的结晶度降低。薄膜的氮元素累积释放率曲线呈"S"型趋势,Ritger-Peppas模型和2次多项式模型拟合较好,相关系数(R2)分别为0.976 3和0.950 9,Ritger-Peppas模型中n为0.816 7,说明氮元素释放规律是扩散和溶蚀综合作用的结果。     

The Pathology of Vinyl Chloride Exposed Mice

Outbred albino laboratory mice were exposed to 50 p.p.m. and 500 p.p.m. vinyl chloride by inhalation 6 hrs./day, 5 days/week during 52 and 26 weeks, respectively. Pathologic examination showed the presence of histologically benign alveologenic lung adenomas, haem-angiosarcomas in fat tissue as well as a few benign and malignant tumours at various sites. Only one liver haemangiosarcoma was noted. All animals exposed to 500 p.p.m. developed tumours; 71 % of the animals given 50 p.p.m. were tumour bearing. The frequency of all tumours, number of tumour foci and size of foci in both groups suggest a dose-dependent carcinogenic effect of vinyl chloride. Haemocoelia due to blood vessel rupture was a common cause of death. Telangiectasis of the liver was also observed in a few animals. The role of fat tissue as well as blood vessel involvement in the pathology of vinyl chloride is discussed.     

PET fabric supported fixed site carrier membrane for selective metal ion transport

Development of a novel fixed site carrier membrane (FCM), supported by PET fabric for metal ion separation is reported. The membranes were prepared by dipping PET fabric into the methylene chloride solution of Poly(5-vinyl-m-phenylene-m′-phenylene-32-crown-10)_ (P(VCE)), a polymeric metal ion carrier. It was found that the flux of mono-valent metal ion transported across the membrane is significantly differed from each other and the flux decreases in the order Cs⁺>Rb⁺>K⁺>Na⁺>Li⁺ irrespective to the anion except perchlorate anion. It was explained in terms of the stability of the complex, formed by crown ether unit of the P(VCE) and the various metal ions, meanwhile, the lower rate of transport in the presence of perchlorate anion was ascribed to its low hydrophilicity.     

Aroma finishing of PET fabrics with PVAc nanoparticles containing lavender oil

A durable aroma finishing for PET fabric was carried out by adopting poly(vinyl acetate) (PVAc) nanoparticles containing lavender oil (LO) in core. Relatively small size of PVAc nanoparticles (ca. 244 nm of mean particle diameter) was expected to resist the frictional destruction of the particles, which is frequently observed in cases of microcapsules. PVAc nanoparticles containing LO in core were prepared by emulsification-diffusion method and their application as an aroma releasing agent for PET fabrics was assessed through the observation of releasing profiles of LO in ethanol for experimental acceleration. Melamine-formaldehyde (MF) microcapsules containing LO were also prepared and treated on fabrics for comparison. PVAc nanoparticles treated on PET fabric showed higher initial releasing amount, which was ascribed to the enhanced surface area. After 2 days of releasing, PET fabric treated with PVAc nanoparticles showed slower and more stable releasing profile and reached about 12 ppm of cumulative release after 16 days, which was under two thirds of that with MF microcapsules. PVAc nanoparticles can be used as an agent for durable aroma finishing of PET fabrics.     

纳米SiO2对聚乙烯醇基复合涂膜包装材料成膜透湿性能的影响

聚乙烯醇（PVA）由于其亲水性能而影响其在食品包装上的应用。本研究采用添加纳米SiO2对聚乙烯醇基复合涂膜包装材料进行改性,利用响应曲面方法研究SiO2、硬脂酸、戊二醛对三元复合涂膜材料成膜效能特性的影响及交互作用。结果表明：加入纳米SiO2可有效提高聚乙烯醇基复合涂膜包装材料的阻水阻湿性能,优化组成膜透湿率（8.18 g•m-2•d-1）比对照组（不添加纳米SiO2的PVA复合膜）降低26.61%（p<0.05）。硬脂酸、戊二醛对复合涂膜材料成膜的透湿率的影响与纳米SiO2存在显著的交互作用,每100 mL 5%（W/VH2O）的PVA溶液中纳米SiO2添加量在小于0.05 g范围内随着其含量增大,复合涂膜材料成膜透湿率随硬脂酸、戊二醛的比例增加而降低,阻水阻湿性能提高。     

Molecular complex of lignosulfonic acid/poly(vinyl pyridine) via ionic interaction: characterization of chemical composition and application to material surface modifications

Poly ion complexes of anionic lignosulfonic acid (LSA) with cationic poly(2-vinyl pyridine) or poly(4-vinyl pyridine) were prepared by mixing the polymer solutions in dimethyl sulfoxide or dilute hydrochloric acid. The complexes were formed as soon as the polymer solutions were mixed. Fourier transform infrared (FTIR) measurements for the complexes revealed the presence of strong ionic interactions between sulfonate anions of LSA and pyridinium cations of the vinyl pyridine (VPy) polymers. The strong interaction was supported by detection of a glass transition temperature (T _g) much higher than pristine T _g values of VPy polymers in differential scanning calorimetry. By using the ionic complexation, a coating of LSA onto VPy polymer films was undertaken to modify their original surface property. Formation of a thin complex film was confirmed by observation of absorption bands that are characteristic of the pyridinium cation in reflection FTIR spectra measurements, and by visualization of the attached LSA component in atomic force microscopy. This treatment resulted in the surface of the VPy polymer films becoming hydrophobic. An adhesion test was also conducted by pasting two veneered woods with the polymer complex, followed by shear-tearing them off. The adhesive strength of the complex was estimated to be 1.1 MPa. Part of this report was presented at the 55th (Kyoto, March 2005) and 56th (Akita, August 2006) Annual Meetings of the Japan Wood Research Society     

黄麻纤维织物增强乙烯酯复合材料的制备与力学性能

织物增强聚合物(TRP)因其具有优异的机械性能而被广泛应用于汽车、建筑等领域。传统TRP材料通常以玻璃纤维、碳纤维作为增强体,由于成本高及不可降解等问题限制了发展和应用。本研究采用可生物降解的天然黄麻纤维为增强体,以乙烯酯为基体树脂,采用模压工艺制备双层黄麻织物增强乙烯酯树脂复合材料。考察经纱和纬纱的取向对复合材料密度、孔隙率及力学性能的影响。通过调整黄麻织物的纱线角度(0°,30°,45°,60°和90°),研究经纬纱角度对复合材料性能的影响,采用的模压成型工艺是80℃、7 MPa条件下压制2.5 h。为了考察模压温度的影响,将纱线角度为60°的试样在40℃的低温条件下(其余条件不变)压制成型。结果表明:与纯乙烯酯相比,黄麻纤维具有一定的增强作用,复合材料的弯曲强度和冲击强度分别提高24.77%和39.83%,拉伸性能降低30.52%。扫描电子显微镜结果显示,复合材料力学强度的提高与纱线间的孔隙分布有关。在研究范围内,经纬纱定向对复合材料的冲击强度影响比较显著。低温(40℃)条件下,制备的定向角为60°时的黄麻纤维增强乙烯基酯复合材料的各项力学性能达到最佳。     

纳米SiO2对PVA基复合涂膜包装材料成膜透湿性能的影响

为改善聚乙烯醇（PVA）涂膜的阻湿保鲜效能特性,该文采用添加纳米SiO2对PVA基复合涂膜包装材料进行改性,应用响应曲面方法研究SiO2、硬脂酸、戊二醛对三元复合涂膜材料成膜效能特性的影响及交互作用。结果表明：加入纳米SiO2改性可有效提高PVA基复合涂膜包装材料的阻水、阻湿性能,优化组成膜透湿率8.18 g/(m2·d)比对照组（不添加纳米SiO2的PVA复合膜）降低26.61%（p<0.05）;硬脂酸、戊二醛对复合涂膜材料成膜透湿率的影响与纳米SiO2存在显著的交互作用,每100 mL 0.05 g/mL的PVA溶液中纳米SiO2添加量在小于0.05 g范围内随着SiO2含量增大,复合涂膜材料成膜透湿率随硬脂酸、戊二醛的比例增加而降低,阻湿性能提高。     

CONTROLLED RELEASE OF FERTILIZER MICROCAPSULES USING ETHYLENE VINYL ACETATE POLYMER TO ENHANCE MICRONUTRIENT AND WATER USE EFFICIENCY

There have as yet been no detailed studies of micronutrient release from polymer coated fertilizers (PCFs). In this research, slow release microcapsules containing iron fertilizer was made and its release pattern evaluated. Three polymers ethyl cellulose (EC), glycerol mono stearate (GMS) and Compritol 888 ATO, were mixed with avicel and lactose and the microcaopsules were made by extrusion/spheronization method. The dissolution test carried out to determine the Fe release rate versus time. The results showed that, microcaopsules containing Compritol 888 ATO, released iron ions slower than that of EC and GMS. The release rate reached 85% after 7 days. In order to reduce the release rate, these microcaopsules were coated with ethylene vinyl acetate (EVA) polymer by dip coating method. It is concluded that the combination of matrix type formulation and the coating with EVA polymer caused a significant decrease in the release rate of iron.