60系列低断面乘用子午线无内胎轮胎研制

采用局部平衡轮廓设计,优化轮胎部位的参数,以求综平衡的６０系列轮胎性能。介绍了轮胎在结构设计、配方设计、工艺条件方面的情况以及该系列的综合性能和社会效益。     

尼龙斜交载重轮胎早期损坏原因及解决方法探讨

针对尼龙余交载重轮胎使用过程中出现的早期损坏，分析了其使用因素和设计因素，从配方设计、结构设计等方面提出了相应的解决方法。同时认为加强工艺控制与结构、配方设计对轮胎性能的影响同等重要。     

人字形花纹输送带的研制

介绍了人字形花纹输送带的研制。主要包括结构设计、模板设计、主体材料的选择，配方设计和工艺设计。经试验测试，产品性能符合Q／FXZ 003-2004标准。     

条状花纹输送带的研制

介绍了条状花纹输送带的研制。主要包括主体材料的选择、配方设计、工艺设计、结构设计和模具设计，经试验检测，产品性能符合Q／FXZ002-2004标准。     

橡胶履带力学分析及优化设计

介绍橡胶履带的力学分析、结构设计和橡胶材料配方设计性能要求。橡胶履带的力学分析是橡胶履带设计的前提。橡胶履带的结构和橡胶材料配方设计应满足履带结构性能和使用性能的要求。     

重型汽车U型吸空管的研制

针对重型汽车U型吸空管使用条件和技术要求,进行了产品结构、胶料配方和工艺设计。结果表明,研制产品各项性能均符合用户要求;工艺及结构设计适宜,螺旋钢丝层能够承受-20kPa压力,不塌瘪。     

数值模拟技术在橡胶制品开发中的应用

结合数值模拟技术,并配合获得成功的应用案例,主要从橡胶制品开发的各个环节,包括产品性能预测及结构优化、胶料配方设计、模具结构设计以及硫化工艺设计等,对数值模拟技术的应用进行了介绍。     

景区游览车聚合物复合材料车体的研制

本文介绍了一种聚合物复合材料景区游览车车体的结构设计，材料选择，配方设计，模具和产品制备过程，以及制品性能检测和应用结果，结果表明，所研制的聚合物复合材料景区游览车车体的结构设计，材料选择，配方设计合理，模具和产品制备工艺符合大尺寸游览车的性能要求，车体制品性能经检测符合行标要求，经现场应用考核可知，能满足景区游览用的需要。由此可知，聚合物复合材料的构件可望在轻轨列车甚至高速列车上，具有广泛的应用前景。     

80.75系列扁平化子午线载重轮胎的研制

运用轮胎整体结构设计法，开发研制出８０，８５系列低断面无内胎全钢丝子午线载重轮胎。介绍了轮胎结构设计，配方设计，主要工艺条件等研究内容，以及产品性能，社会经济效益等方面的情况。     

防滑耐磨高强度复合型PVC塑胶跑道的加工技术

以最新研发配方和独特的结构设计生产防滑耐磨高强度复合型PVC塑胶跑道。探讨了硅烷偶联剂对粉煤灰(PFA3)表面活化处理及在废旧纸塑混合材料与PVC配方体系共混的改性机理,工艺及制备方法。探讨了复合型PVC塑胶跑道的配方及层面结构设计。结果表明:以最新研发的复合型PVC塑胶跑道配方及结构设计,经挤出、压延生产的PVC塑胶跑道,在物料的塑化性能、加工稳定性及产品的耐磨防滑、抗冲稳定性等性能方面都得到了改善和提高。     

Improved operating scenarios for the production of acrylonitrile‐butadiene emulsions

This article focuses on important aspects related to the production of acrylonitrile‐butadiene rubber (nitrile rubber or NBR) emulsions using a train of eight continuously stirred tank reactors. The first aspect we discuss concerns miscellaneous operating procedures, targeted toward achieving desired properties of the NBR emulsion and at the same time reducing the amount of off‐spec material during the transient period. In one of the operating procedures discussed, the first reactor is started full of “batch recipe,” whereas the remaining reactors in the train are half full with all reaction ingredients. In another case, we discuss an alternative design scenario, where the first reactor in the train is of a much smaller volume compared with the following reactors. The benefits of these two operating (production) scenarios are illustrated by comparison of different polymer and latex properties obtained with the commonly used procedures. Second, we discuss a novel criterion that can quantitatively distinguish between Cases I and II kinetics emulsion polymerization behavior with respect to continuous reactor stability (oscillatory behavior). Finally, additional feed policies are addressed, such as splitting the more reactive monomer and/or other reaction ingredients among the reactors of the train for better control of certain desired properties. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Interface morphology and phase separation in polymer-dispersed liquid crystal composites

It is widely appreciated that electro-optic activity in polymer-dispersed liquid crystals (PDLCs) depends on separation of the polymer and liquid crystal (LC) phases. Since the phase structure develops in a non-equilibrium system, the morphology of the LC domains depends on the details of the chemical and physical processes active during domain formation. The nature of the interface between the polymer and liquid crystal phases is of particular interest. This work discusses the two-phase morphology in an acrylate-based system that develops during polymerization-induced phase separation (PIPS). Using small-angle X-ray scattering (SAXS) and ultra-small-angle X-ray scattering (USAXS), we find that interfaces in PDLCs developed from an acrylate-based recipe are more disordered than generally appreciated. Information gained from SAXS and USAXS is compared to data from scanning electron microscopy (SEM) and transmission electron microscopy (TEM). To elucidate the apparent discrepancies between imaging and scattering, we investigated the effects of SEM sample preparation. We observe significant alteration of the interface morphology due to the leaching of the LC phase.     

Pervaporation with Latex Membranes: A Study on Membrane and Pervaporation Effects

Abstract

The separation process is affected by a number of factors related to the membrane itself and the operation conditions. For latex membrane systems, factors such as feed concentration and feed temperature are found to affect pervaporation properties similarly to solvent-cast membrane systems. However, effects relating to polymer structure and latex particle morphology are more complicated for latex membrane systems. The separation performance depends upon the combined contribution of all the effects. It is shown that effects which make a latex membrane achieve a higher degree of film fusion, or make the polymer more rigid, will raise the membrane selectivity and decrease the permeation rate. A good latex membrane can be obtained by balancing all the effects pertaining to polymer, particle, and film structure and morphology.     

Porous polymer carbons. II. Preparation and properties of porous poly(vinylidene chloride) carbons

Suspension–polymerized copolymers of vinylidene chloride and ethylene glycol dimethacrylate have been converted into carbons by heating to 900°C. Poly(vinylidene chloride) homopolymer may melt on a first-stage heating at ca. 200°C and consequently yields a fused 900°C carbon; restraining the first-stage heating to slightly lower temperatures permits the retention of the polymer morphology which is then retained on subsequent carbonization at 900°C. The crosslinked copolymers do not fuse at 200°C and lose the dimethacrylate component, apparently cleanly, in the temperature range of 350–450°C and give 900°C carbons which are shrunken pseudomorphs of the parent polymer; all structural features are retained, including the characteristic skin of the polymer particles. Thus, the macroporous character of the carbons is controlled by both the crosslinker and diluent contents of the original polymerization recipe. The 900°C carbons are also microporous; hysteresis in nitrogen (77°K) isotherms is attributed to activated diffusion since carbon dioxide (196°K) isotherms are reversible. The microporosity of these dual-porosity carbons depends on the content of crosslinking comonomer in the parent polymer, and possible reasons for this dependence are discussed.     

ELECTROINDUCED DISPERSIVE POLYMERIZATION OF METHYL METHACRYLATE IN AQUEOUS MEDIA

The electroinduced and chemical dispersion polymerization of methyl methacrylate was performed in aqueous methanol solution (water/methyl alcohol ratio 50/50 by wt%) in the presence of poly(vinyl pyrrolidone) as a stabilizer with ceric sulfate as an initiator. The effects of various polymerization parameters, for example concentrations of recipe ingredients, temperature, potential, and duration, on polymerization yield were examined. In all cases higher yield was obtained with the electrochemical polymerization procedure. Initiation rates of polymerization processes, thermal properties of polymers, interaction of initiator with monomer and stabilizer were investigated in detail. Possible structure of polymer is proposed, and a tentative polymerization mechanism is suggested.     

Computational design of structured chemical products

In chemical product design, the aim is to formulate a product with desired performance. Ingredients and internal product structure are two key drivers of product performance with direct impact on the mechanical, electrical, and thermal properties. Thus, there is a keen interest in elucidating the dependence of product performance on ingredients, structure, and the manufacturing process to form the structure. Design of product structure, particularly microstructure, is an intrinsically complex problem that involves different phases of different physicochemical properties, mass fraction, morphology, size distribution, and interconnectivity. Recently, computational methods have emerged that assist systematic microstructure quantification and prediction. The objective of this paper is to review these computational methods and to show how these methods as well as other developments in product design can work seamlessly in a proposed performance, ingredients, structure, and manufacturing process framework for the design of structured chemical products. It begins with the desired target properties and key ingredients. This is followed by computation for microstructure and then selection of processing steps to realize this microstructure. The framework is illustrated with the design of nanodielectric and die attach adhesive products.     

Lack of Contribution of p66shc to Pressure Overload-Induced Right Heart Hypertrophy

The leading cause of death in pulmonary arterial hypertension (PAH) is right ventricular (RV) failure (RVF). Reactive oxygen species (ROS) have been suggested to play a role in the development of RV hypertrophy (RVH) and the transition to RVF. The hydrogen peroxide-generating protein p66shc has been associated with left ventricular (LV) hypertrophy but its role in RVH is unclear. The purpose of this study was to determine whether genetic deletion of p66shc affects the development and/or progression of RVH and RVF in the pulmonary artery banding (PAB) model of RV pressure overload. The impact of p66shc on mitochondrial ROS formation, RV cardiomyocyte function, as well as on RV morphology and function were studied three weeks after PAB or sham operation. PAB in wild type mice did not affect mitochondrial ROS production or RV cardiomyocyte function, but induced RVH and impaired cardiac function. Genetic deletion of p66shc did also not alter basal mitochondrial ROS production or RV cardiomyocyte function, but impaired RV cardiomyocyte shortening was observed following PAB. The development of RVH and RVF following PAB was not affected by p66shc deletion. Thus, our data suggest that p66shc-derived ROS are not involved in the development and progression of RVH or RVF in PAH.     

Optimization and Control of Pressure Swing Adsorption Processes Under Uncertainty

The real‐time periodic performance of a pressure swing adsorption (PSA) system strongly depends on the choice of key decision variables and operational considerations such as processing steps and column pressure temporal profiles, making its design and operation a challenging task. This work presents a detailed optimization‐based approach for simultaneously incorporating PSA design, operational, and control aspects under the effect of time variant and invariant disturbances. It is applied to a two‐bed, six‐step PSA system represented by a rigorous mathematical model, where the key optimization objective is to maximize the expected H₂ recovery while achieving a closed loop product H₂ purity of 99.99%, for separating 70% H₂, 30% CH₄ feed. The benefits over sequential design and control approach are shown in terms of closed‐loop recovery improvement of more than 3%, while the incorporation of explicit/multiparametric model predictive controllers improves the closed loop performance. © 2012 American Institute of Chemical Engineers AIChE J, 59: 120–131, 2013     

Identification of the active species in the suppression of postirradiation conductivity in polystyrene films for dosimeter application

The resistivity of insulating materials for electrostatic, ion chamber dosimeters must be very high and must remain so after exposure to ionizing radiation. Low dielectric polarization and good fabrication characteristics make hydrocarbon polymers most suitable, but both the conductivity during irradiation and its decay afterward vary greatly even for the same type of polymer, probably depending on impurities. Amorphous, styrene-based polymers and copolymers polymerized in aqueous emulsion and initiated with K₂S₂O₈ were found to have much more rapid decay of conductivity after irradiation than pure polystyrene or other nonpolar polymers. The synthesis method incorporates sulfate groups on the polymer chain ends and leaves emulsifier residues distributed throughout the polymer as was demonstrated by various analytical procedures. To identify the trapping species a synthesis program was carried out varying selected ingredients in the polymerization recipe. It was found that the postirradiation conductivity was not dependent on the chemical nature of the emulsifier residues. On the other hand, the decay time of conductivity after irradiation did depend on the polar groups incorporated in the polymer chain. It was concluded that effective charge carrier traps were constituted of a polar second phase highly dispersed through the polymer by association with polar groups incorporated on the polymer chain.     

The influence of N-vinyl-2-pyrrolidinone in polymerization of holographic polymer dispersed liquid crystals (HPDLCs)

Holographic polymer dispersed liquid crystals (HPDLCs) are targeted for application in a wide range of devices as dynamically switchable transmission or reflection diffraction gratings tunable through the visible spectra. The inclusion of N-vinyl pyrrolidinone (NVP) has been shown to reduce liquid crystal (LC) droplet size in HPDLC gratings and subsequently improve HPDLC performance. In this work, the influence of NVP on HPDLC polymer/LC morphology is examined and correlated to the influence of NVP on HPDLC photopolymerization kinetics and LC phase separation. As in other photopolymer systems, NVP significantly increases the rate of polymerization in HPDLC photopolymerization. In all the HPDLC formulations studied, NVP is completely incorporated into the polymer network while less than half of acrylate double bonds react. Furthermore, as the highly cross-linked polymer network forms, the small mono-vinyl NVP appears to react preferentially with acrylate double bonds, facilitating additional conversion of pendant double bonds otherwise trapped in the polymer network. NVP also induces a delay in the onset of reaction diffusion termination and extends the range of conversions for which reaction diffusion is observed. Interestingly, NVP also impacts polymer/LC morphology by delaying LC phase separation to higher double bond conversions. Together, the influence of NVP on the polymerization kinetics and LC phase separation alters HPDLC morphology by limiting LC droplet size, consequently resulting in improved HPDLC performance.