国内PVC材料所用胶粘剂概况

综述近十余年来国内PVC材料所用胶粘剂的研究进展,分类介绍丙烯酸酯类胶粘剂、聚氨酯类胶粘剂、改性过氯乙烯胶粘剂、醋酸乙烯类胶粘剂、氯丁橡胶胶粘剂和环氧树脂类胶粘剂用于PVC材料的粘接概况,讨论了各种胶粘剂所适用的PVC材料范围,并通过剥离强度,粘接强度等主要性能指标分析了各胶粘剂的主要性能。     

Association of ethylene vinyl acetate copolymer in dilute solutions. V. Stability and pour point depression to wax solutions

The stability of two kinds of aggregation states of ethylene vinyl acetate (EVA) copolymer in dilute solution of 1,2‐dichloroethane has been investigated by viscometry. It was found that good storage‐time, shearing, and dilution resistance were displayed for both states of EVA molecule with intra‐ and interchain association. And for the pour point depression of wax solution doped with EVA, the EVA in intrachain aggregation state was better than the EVA in interchain aggregation state. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 836–841, 2000     

Impact strength and dynamic mechanical properties correlation in elastomer‐modified polypropylene

This article describes the impact and dynamic mechanical properties of rubber‐modified binary blends of polypropylene (PP). Two conventional elastomers [viz. ethylene vinyl acetate copolymer (EVA) and ethylene propylene diene terpolymer (EPDM)] were used as an impact modifier for PP. It is clearly indicated by the results that EPDM is better than EVA as an impact modifier of PP. Analysis of data of dynamic mechanical properties and impact properties at various compositions of the blends revealed a direct correlation between impact properties and dynamic mechanical loss tangent. The energy dissipation due to viscoelastic relaxation is therefore suggested as a mechanism of impact toughening of PP, in addition to the other commonly known mechanisms of toughening (viz. shear yielding and crazing induced by deformation of rubber‐phase domains). © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 962–971, 2000     

Polyblend fibers from polypropylene and mercapto-modified EVA

Polyblend fibers were made from mixtures of polypropylene (PP) and ethylene-vinyl acetate copolymers (EVA) or their mercapto-modified products [poly(ethylene-co-vinyl acetate-co-vinyl mercaptoacetate)] (EVASH). The presence of few EVA or EVASH in the PP fibers results in an increasing of the elastic modulus, indicating a reinforcing action of these functional polymers. The composition surface of the modified PP fibers was analyzed by X-ray photoelectron spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2243–2249, 1997     

Melt functionalization of EVA copolymers with maleic anhydride

Ethylene vinyl acetate (EVA) copolymers with different amounts of vinyl acetate were melt‐functionalized with maleic anhydride. The effect of benzoyl peroxide, t‐butyl perbenzoate, and dicumyl peroxide (DCP) as free‐radical initiators on the functionalization performance was studied. The crosslinking reactions occur to a larger extent than in polyethylene, indicating that the vinyl acetate groups favor the formation of free radicals. From all the experiments performed in this study, the recommended initiation system to achieve the best values of the functionalization degree and the lower gel content involves the use of DCP in a concentration of about 0.3 wt % and a maleic anhydride concentration around 5.0 wt %. From FTIR and TGA analyses, it is suggested that the hydrogen abstraction in the EVA copolymers occurs both in the methyl group of the acetate moiety and in the tertiary C—H. The free radicals generated in the tertiary C—H react with maleic anhydride in a higher proportion. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1799–1806, 1999     

Evaluation of EVA–PVAc blend behavior by 1‐D and 2‐D solid‐state NMR

Ethylene‐co‐vinyl acetate and poly(vinyl acetate) blends were prepared in different proportions by melting in a HAAKE Rheomix mixer. The blends were prepared at a fixed temperature, rotation rate, and processing time. High‐resolution solid‐state nuclear magnetic resonance was chosen to characterize the blends with respect to structure–mobility–compatibility employing magic angle spinning with cross polarization and high‐power hydrogen decoupling and the measurements of the proton spin–lattice relaxation time in the rotating frame (Tρ). The miscibility between polymer chains was also studied by two‐dimensional ¹H–¹³C shift correlation (HETCOR). © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 221–226, 1999     

Solid‐state NMR and morphological studies of poly(ethylene‐co‐vinyl acetate)/poly(vinyl acetate) blends

To obtain a correlation among structure–morphology–mobility–compatibility properties of poly(ethylene‐co‐vinyl acetate) (EVA)/poly(vinyl acetate) (PVAc) blends, we have used scanning electron microscopy and solid‐state nuclear magnetic resonance in our investigations. The results are discussed in terms of blends, component dispersion, plasticization effect, and domain mobilities to acquire a response of the correlation between structural properties. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2990–2996, 1999     

EVA指标在国有企业绩效评价体系中的应用

近年来,国资委对央属企业业绩考核增加了EVA指标。EVA是一套完整的财务管理体系,具体表现为EVA评价指标,它通过税后净营业利润减去资本成本的余额来衡量股东利益。国有企业以EVA指标作为业绩考核的核心指标,可以客观地评价企业管理者的经营绩效,有利于国有企业以长期价值创造、经营效率为中心,促进国有资产可持续价值的实现。     

注射超轻EVA/Fusabond材料的交联发泡动力学

注射硫化交联发泡成型的乙烯-乙酸乙烯酯共聚物(EVA)与马来酸酐接枝的乙烯-丙烯酸酯的共聚物(Fusabond)超轻发泡材料,其力学性能符合adidas鞋材标准,可用于生产注射adidas运动鞋中底;利用流变仪测定转矩和发泡压力随时间的变化来研究其硫化交联反应和发泡作用的动力学,在转矩上升阶段为一级反应,给出了硫化交联反应的速率常数k为1.74×10-2s-1,表观活化能E为108kJ/mol,频率因子A为6.81×1010;发泡作用的速率常数kb为1.32×10-2s-1,表观活化能Eb为58.2kJ/mol,频率因子Ab为8.10×107。     

经济增加值考核办法在发电企业中的运用分析

针对国务院国有资产监督管理委员会2009年12月28日颁布的《中央企业负责人经营业绩考核暂行办法》(以下简称第22号令),从经济增加值(economic value added,EVA)的概念和理财观念入手,深入剖析了第22号令中关于EVA的主要内容,结合发电企业所具有的资源密集、技术密集和资本密集等特点,对EVA在发电企业的运用进行了研究。提出以下观点:应设置股本资本成本,控制股权资本规模;将研发费用支出从当期净利润指标中剔除;将项目筹建费用从损益中剔除;将在建工程等非经营性资产从考核中剔除。