Structural modeling and analysis of FRP composite product subsystems—A systems approach

This study derives a new mathematical model aimed to consider virtual design and manufacturing procedures for developing highly competitive, complex geometry composite products for various engineering applications. The fiber‐reinforced polymer (FRP) composite industry faces several critical issues right from selection (of product, process, equipment, tooling, materials) to manufacturing the final products by meeting several design criteria and customer requirements. An attempt has been made in this article to identify different subsystems and other constituents of five main systems–resin system, reinforcement system, process equipment, tooling system, and product design of total composite product system. Intermediate processes, alternative designs, process sequence, technological changes, chemical reactions, and other performance affecting parameters have been discussed. Graph theoretical models, variable permanent adjacency matrix models, and permanent functions of these systems based on graph theory–matrix algebra–permanent function methodology are developed. Analytical tests for structural analysis of composite product system are derived to select optimum constituents in each of these five systems of composite product. Coefficient of similarity and dissimilarity are useful aid to take right decision between alternative solutions. Permanent function is a unique representation and to be used by composite industry for coding, evaluation, comparison, ranking, and optimum selection. Structural models are useful for basic understanding of complete composite product system, leading to right decisions for manufacturing and business strategies. Step‐by‐step procedure is developed to assist composite industry to implement the proposed method in a right way. Usefulness of the proposed methodology to composite industry is also presented. POLYM. COMPOS., 27:681–699, 2006. © 2006 Society of Plastics Engineers     

Epoxy/alumina nanoparticle composites. II. Influence of silane coupling agent treatment on mechanical performance and wear resistance

Two silane coupling agents (SCAs) were used to treat alumina nanoparticles to improve nanoparticle dispersion into the polymer matrix. [3‐(2‐Aminoethylamino)‐propyl]‐trimethoxysilane [a reactive silane coupling agent (RSCA)] was able to form covalent bonds with both the reinforcing agent (alumina nanoparticles) and the epoxy matrix, whereas 3‐(trimethoxysilyl) propyl methacrylate (a nonreactive SCA) could not covalently interact with the epoxy resin. The strengthening of the filler–matrix interactions by means of covalent bonds resulted in improved flexural strength, strain, and especially, wear resistance. The wear rate and the weight loss of the RSCA‐treated alumina nanoparticle composite were the best among the investigated composite samples and equal to these of the neat epoxy matrix. This improvement was due to better nanoparticle dispersion, a result of the SCA treatment of the alumina nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4410–4417, 2006     

Moisture absorption modeling using design of experiments

The effect of temperature and humidity on equilibrium moisture content of laminates was studied by response surface design. Two glass fabric‐reinforced laminated composite materials with different epoxy matrix resins, laminates A and B, were studied. Laminates A and B used are cyanate ester and polyphenylene oxide modified epoxy based laminate, respectively. The results show that the response surface profiles of moisture absorption for the two laminate materials are similar though their amounts of moisture absorption are different. The temperature‐humidity interaction effect and the quadratic effect of temperature are significant for laminate A. However, only the linear effects of temperature and humidity are significant for laminate B. Predictive models relating the important factors to the equilibrium moisture content were proposed in the article. The models developed can be used to predict and assess the reliability of the laminates for moisture related failures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1539–1543, 2007     

Interfacial interaction,morphology, and tensile properties of a composite of highly crystalline cellulose and maleated polypropylene

A composite of highly crystalline cellulose was synthesized via a melt‐mixing method with maleic anhydride (MA)‐grafted polypropylene (PP), MAPP, which was prepared by melt‐mixing PP with 0.25–8.0 phr (part of reagent per hundred parts of PP) of MA, and the morphology and tensile properties were examined with respect to the interfacial interactions of MAPP and cellulose. The graft degree (G_d) of MAPP increases with an increase in the initial MA amount up to 2.5 phr, beyond which it decreases because of the remaining of more free MA monomers and/or the formation of more oligomers remaining in the matrix. The morphology and tensile properties of the composite are affected strongly by G_d as well as the presence of the free MA in the matrix. For the MAPP without any free MA, even the G_d value as small as 0.25–0.5 wt % yields a maximal tensile strength. The existence of free MA monomers in the MAPP decreases the tensile strength, probably because of interrupting the interactions of the grafted MA groups with the OH groups of cellulose. The tensile properties of the composite correlate with the interfacial adhesion as well as the dispersion of cellulose microfibers in the matrix, both of which are determined by the interactions of the OH groups on cellulose with the grafted MA groups. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3830–3841, 2006     

Creep characterization of vapor‐grown carbon nanofiber/vinyl ester nanocomposites using a response surface methodology

The effects of selected factors such as vapor‐grown carbon nanofiber (VGCNF) weight fraction, applied stress, and temperature on the viscoelastic responses (creep strain and creep compliance) of VGCNF/vinyl ester (VE) nanocomposites were studied using a central composite design (CCD). Nanocomposite test articles were fabricated by high‐shear mixing, casting, curing, and post curing in an open‐face mold under a nitrogen environment. Short‐term creep/creep recovery experiments were conducted at prescribed combinations of temperature (23.8–69.2°C), applied stress (30.2–49.8 MPa), and VGCNF weight fraction (0.00–1.00 parts of VGCNF per hundred parts of resin) determined from the CCD. Response surface models (RSMs) for predicting these viscoelastic responses were developed using the least squares method and an analysis of variance procedure. The response surface estimates indicate that increasing the VGCNF weight fraction marginally increases the creep resistance of the VGCNF/VE nanocomposite at low temperatures (i.e., 23.8–46.5°C). However, increasing the VGCNF weight fraction decreased the creep resistance of these nanocomposites for temperatures greater than 50°C. The latter response may be due to a decrease in the nanofiber‐to‐matrix adhesion as the temperature is increased. The RSMs for creep strain and creep compliance revealed the interactions between the VGCNF weight fraction, stress, and temperature on the creep behavior of thermoset polymer nanocomposites. The design of experiments approach is useful in revealing interactions between selected factors, and thus can facilitate the development of more physics‐based models. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42162.     

Injection molding product weight: Online prediction and control based on a nonlinear principal component regression model

Weight is an important quality characteristic of injection‐molding products. The current work focuses on the online prediction and closed‐loop control of the product weight. Previous researchers used the process set‐points as the inputs to establish weight prediction model. These models cannot reflect the weight variations at a given setting. In this study, an online weight prediction model has been developed, with the process variable trajectories as the inputs, using a principal component regression (PCR) model. A nonlinear enhancement has been made to improve the prediction accuracy of the PCR weight model. Based on such an online prediction, a closed‐loop weight control system has been developed and tested experimentally. POLYM. ENG. SC. 46:540–548, 2006. © 2006 Society of Plastics Engineers     

质量管理体系在涂料新产品研发中的作用

质量管理是企业科学管理的核心内容。如何做好涂料新产品研发的质量管理工作,是涂料新产品研发取得成功、实现产品利润最大化和获得竞争优势的重要保障。主要针对目前大多涂料企业对新产品研发过程实行质量管理的认识误区,说明了涂料企业新产品研发过程中质量管理的重要性,希望对涂料企业新产品研发质量管理体系的建立有所帮助。     

Preparation and characterization of alginate and hydroxyapatite‐based biocomposite

In this article, we report a novel route for the preparation of alginate‐hydroxyapatite biocomposite. Hydroxyapatite has been nucleated on alginate chains by precipitation method to obtain a biomimetic artificial bone‐like composite. The composite was characterized by powder XRD, FTIR, TGA, DTA, and SEM to ascertain its phase homogeneity and particle size distribution. Hydroxyapatite particles on alginate matrix are around 500–1000 nm in diameter. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5162–5165, 2006     

Investigation of an N‐Butyl‐N‐(2‐Nitroxyethyl)Nitramine (BuNENA) Process: Identification of Process Intermediates,By‐Products and Reaction Pathways

A process for N‐butyl‐N‐(2‐nitroxyethyl)nitramine (BuNENA) was investigated: Step 1 involves N‐butyl‐ethanolamine addition to 98% HNO₃ to form a salt mixture; Step 2 is addition of acetic anhydride/acetyl chloride catalyst to the salt mixture. A number of potential intermediates, by‐products, and decomposition products from this process were identified/synthesized for use as analytical standards. BuNENA process reaction pathways/mechanisms were elucidated, including the nature of the amine salt solution formed in Step 1. In addition, potential pathways that could account for by‐product formation were elaborated. A study of the consumption of acetyl nitrate in Step 2 was undertaken to prevent its build‐up.     

Surface characteristics of untreated and modified hemp fibers

Natural cellulosic fibers, including hemp, are increasingly being used for composite reinforcement. However, their poor adhesion with synthetic resins limits their use as reinforcing agent. It is generally accepted that interfacial adhesion can be best described in terms of dispersion forces and acid–base interactions. Therefore, there is a need for quantitative determination of acid–base character of natural cellulosic fibers. In this study, acid–base characteristics and dispersion component of surface energy of hemp fibers have been determined using inverse gas chromatography. Effect of alkalization and acetylation on acid–base characteristics has also been examined. The results indicate that alkalization and acetylation make the hemp fiber amphoteric, thereby improving their potential to interact with both acidic and basic resins. Finally, a parallel is drawn between the changes in fiber‐matrix acid–base interactions and the actual improvement in the mechanical properties of the composites manufactured using resin transfer molding process. POLYM. ENG. SCI. 46:269–273, 2006. © 2006 Society of Plastics Engineers     

Engineering an Anti‐Graffiti System: A Study in Industrial Product Design

The objective of this work was to develop products for the anti‐graffiti market using a product design framework that takes into account the company core practices and meets customer expectations. Product development comprised several concurrent steps including market research and analysis to determine the market potential using a Quality Functional Deployment tool. From market research it was estimated that anti‐graffiti products had significant potential within Australia. A range of technical and quality parameters were tested. The Hildebrand and Hansen solubility parameters, viscosity and diffusivity estimates were mainly used for technical evaluation of products. An iterative process was used throughout in conjunction with parameter restraints to meet environmental sustainability, waste reduction and minimize resource consumption. The result was a cost effective product, tailored to customer expectations.     

A grand model for chemical product design

Chemical engineering has been expanding its focus from primarily business-to-business products (B2B) to business-to-consumer (B2C) products. The production of B2B products generally emphasizes on process design and optimization, whereas the production of B2C products focuses on product quality, ingredients and structure. Market and competitive analysis, government policies and regulations have to be explicitly considered in product design. All these considerations are accounted for in the Grand Product Design Model, which consists of a process model, a property model, a quality model, a cost model, a pricing model, an economic model as well as factors such as company strategy, government policies and regulations. This article introduces the model and highlights selected aspects of the model with two case studies. One is a die attach adhesive that illustrates how pricing affects profitability, and how product composition changes with market conditions. Another is a hand lotion that illustrates how product quality affects the profit.     

轮胎专用复合天然橡胶的发展趋势

轮胎专用复合天然橡胶是专门用于轮胎生产加工的天然橡胶的特殊称呼,这类橡胶产品的工艺技术是对传统的天然橡胶初加技工艺术的革新和改造。该类产品从工艺流程、产品质量、市场竞争力都比以往的天然橡胶标准产品更受下游厂家的认可,有更大的竞争优势。但它的发展也面临着重重困难,包括从原料控制、工艺监督、成品销售等方面还需要等待实践的检验、产业的规划发展等多重因素的影响。对轮胎专用复合天然橡胶的发展进行中长期发展规划,让它的发展能在市场上占有一席之地,这是对现有橡胶初加工企业的一种升级改造,也不断促进天然橡胶产业经济可持续发展。     

Influence of interfacial phenomena on the mechanical properties of particulate composite membranes

New models are proposed to describe the mechanical behavior of particulate composite membranes. The mechanical properties of particulate composite membranes are strongly influenced by interfacial phenomena. When adhesion between the filler particles and matrix is poor, the mechanical properties of composite membranes deteriorate with the addition of filler to the matrix. The addition of filler particles to the matrix has a reinforcement effect when adhesion between the particles and matrix is good. The presence of interphase (interfacial shell) around the particles can strongly influence the mechanical properties of particulate composite membranes. Some of the key factors affecting the mechanical properties of composite membranes are interphase‐to‐matrix moduli ratio, core‐to‐shell moduli ratio, and shell‐to‐core radii ratio. Theproposed models are verified using 15 sets of experimental data on the mechanical properties of particulate composites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Dynamic risk analysis using alarm databases to improve process safety and product quality: Part II—Bayesian analysis

Part II presents step (iii) of the dynamic risk analysis methodology; that is, a novel Bayesian analysis method that utilizes near‐misses from distributed control system (DCS) and emergency shutdown (ESD) system databases—to calculate the failure probabilities of safety, quality, and operability systems (SQOSs) and probabilities of occurrence of incidents. It accounts for the interdependences among the SQOSs using copulas, which occur because of the nonlinear relationships between the variables and behavior‐based factors involving human operators. Two types of copula functions, multivariate normal and Cuadras–Augé copula, are used. To perform Bayesian simulation, the random‐walk, multiple‐block, Metropolis–Hastings algorithm is used. The benefits of copulas in sharing information when data are limited, especially in the cases of rare events such as failures of override controllers, and automatic and manual ESD systems, are presented. In addition, product‐quality data complement safety data to enrich near‐miss information and to yield more reliable results. Step (iii) is applied to a fluidized‐catalytic‐cracking unit (FCCU) to show its performance. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Preparation and barrier property of poly(ethylene terephthalate)/clay nanocomposite using clay‐supported catalyst

Poly(ethylene terephthalate) (PET)/clay nanocomposite was prepared by the direct polymerization with clay‐supported catalyst. The reaction degree of catalyst against the cation exchange capacity of clay was 8 wt %. The intercalation of PET chains into the silicate layers was revealed by X‐ray diffraction studies. SEM morphology of the nanocomposite showed a good dispersion of clay‐supported catalyst, ranging from 30 to 100 nm. The intercalated and exfoliated clay‐supported catalyst in PET matrix was also observed by TEM. The improvement of O₂ permeability for PET/clay‐supported catalyst composite films over the pure PET is approximately factors of 11.3–15.6. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4875–4879, 2006     

Mass transfer of dilute 1,2‐dimethoxyethane aqueous solutions during pervaporation process

Pervaporation of 1,2‐dimethoxyethane (1,2‐DME) is evaluated by crosslinked oligosilylstyrene–poly(dimethylsiloxane) composite membranes. A low flow velocity of the feed solution (1.0 L/min), corresponding to a Reynolds number of 220, is used. The pervaporation models are developed by combining the resistance in series and solution–diffusion models. The effects of the boundary layer on the performance of pervaporation are estimated by comparing experimental and theoretical data. The permeation fluxes of 1,2‐DME and water fit very well with the calculated data from the models, but a deviation of the separation factor between the experimental and theoretical data is observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:2075–2084, 2006     

Computer simulation of the damage evolution of fiber‐reinforced polypropylene‐matrix composites with matrix defects

The damage evolution of fiber‐reinforced polypropylene‐matrix composites with matrix defects was studied via a Monte Carlo technique combined with a finite element method. A finite element model was constructed to predict the effects of various matrix defect shapes on the stress distributions. The results indicated that a small matrix defect had almost no effect on fiber stress distributions other than interfacial shear stress distributions. Then, a finite element model with a statistical distribution of the fiber strength was constructed to investigate the influences of the spatial distribution and the volume fraction of matrix defects on composite failure. The results showed that it was accurate to use the shear‐lag models and Green's function methods to predict the tensile strength of composites even though the axial stresses in the matrix were neglected. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 64–71, 2007     

Mathematical modeling and numerical simulation for nucleated solution flow through slit die in foam extrusion

Nucleated solution flow models have been previously developed by Baldwin and coworkers to aid modular design of the foam extrusion process. A framework of previously developed design models is applied here to investigate the flow of nucleated polypropylene–CO₂ solution system. Refinement to the design models is introduced through viscosity reduction factors and Redlich‐Kwong equation of state to describe nonideal gas. These models incorporate temperature and concentration dependency of viscosity, surface tension, and solubility. Simulated results of pressure profiles and volumetric flow rates using a power law rheological equation are compared with experimental values from a three pressure tapping slit die. The influence of temperature on the profiles and its effect on design models is discussed. Preliminary results show that temperature plays an important role in the categorization of process design models. POLYM. ENG. SCI., 46:751–762, 2006. © 2006 Society of Plastics Engineers     

矿产品销售竞争能力的定量分析

矿产品的质量、价格及供货的可靠性是确定市场销售竞争能力的主要因素。采用等价量系数并以此求出可比到厂价来定量分析矿产品的销售竞争能力。通过实例加以说明。