Swelling behavior of polymeric membranes to metalworking fluids

In some working places, such as metal manufacturing or automotive services, mechanical hazards commonly occur along with chemical hazards, particularly metalworking fluids (MWFs). The presence of these chemicals could modify the properties of gloves made from polymeric materials and thus reduce their protective properties against chemical contamination (solvent, MWFs) and mechanical risks (puncture and cutting). This work focused on determining the swelling characteristics and the resistance of six polymeric membranes which were exposed to seven industrial MWFs. We found that the swelling tests can be used to classify the potential of coating polymers in descending order of their resistance to MWFs: nitrile, polyurethane > poly(vinyl chloride), neoprene > butyl, latex. The analysis by multiple linear regression showed, for the first time, that the density or the viscosity‐gravity constant of the fluid and Hansen's solubility parameters of the polymers have a significant impact on the swelling of polymer. For the first time, two new multiple regression models have been proposed, to predict the swelling phenomena of polymers under various MWFs with an accuracy of ≈80%. The effect of temperature on mechanical properties and morphology of material was also examined. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45717.     

Determination of the kinetics of diffusion in coals by solvent swelling techniques

A simple technique has been developed for measuring the kinetics of solvent diffusion in coals at various temperatures. The technique is based on a well-known method for measuring the volumetric swelling of coals by solvents. Several coals have been examined in both pyridine and tetrahydrofuran, at temperatures between 298 and 332 K. The diffusion follows the well-established case II rate law at ambient temperatures, implying that the processes are controlled by relaxation in the coal network structure. As temperatures are increased, the process becomes more Fickian in nature. The activation energies for the diffusion-relaxation processes are in the range 31 to 82 kJ mol⁻¹.     

Swelling of coal in relation to solvent electron-donor numbers

Twenty solvents characterized by electron-donor and electron-acceptor number and solubility parameter were used to study the swelling of a hvB coal. It was found that extent of swelling could be correlated with solvent electron-donor number. Mechanisms of swelling include solvent-induced breakage of electron-donor—acceptor interactions between coal macromolecules.     

多嵌段共聚物增容的遇水膨胀橡胶研究

以天然橡胶和吸水树脂（聚丙烯酸钠）为主要原料，以含聚氧化乙烯嵌段的亲水亲油型多嵌段共聚物为增容剂，以活性陶土为补强剂，利用多组分机械共混技术，制备了遇水膨胀橡胶；从吸水动力学数据出发，研究了重量吸水率与增容剂含量、吸水树脂含量之间的关系；对遇水膨胀橡胶吸水前后的力学性能进行了测试。结果表明，增容剂的加入能显著改变遇水膨胀橡胶的吸水性能和力学性能。     

Swelling of compacted sand–bentonite mixtures

Based on the concept that the maximum water volume absorbed by montmorillonite per unit volume is constant, the swelling deformation of sand–bentonite mixtures was characterized using the void ratio of montmorillonite, defined as volume ratio of water to montmorillonite. The relationship between the montmorillonite void ratio and vertical pressure at full swelling is independent on the initial compaction condition and sand–bentonite mixing ratio, and is a straight line in log scales. When the vertical pressure is large enough and/or the content of bentonite in the mixture is small, the measured plots deviate from linearity. Using the concept of skeleton void ratio, a method is proposed and verified for predicting the limited vertical pressure over which the measured plots start to deviate from linearity between the montmorillonite void ratio and vertical pressure.     

Swelling and diffusion characteristics of polar and nonpolar polymers in asphalt

The swelling and diffusion characteristics of a polar polymer [ethylene vinyl acetate (EVA)] and a nonpolar polymer [low-density polyethylene (LDPE)] were studied with swelling experiments of the polymers in asphalt at different temperatures. The study showed that the diffusion mechanisms for LDPE and EVA were different and temperature-dependent. In the case of LDPE, the observed diffusion was anomalous at both swelling temperatures (70 and 90°C). LDPE at 90°C showed sigmoidal solvent-uptake behavior during the initial period of swelling and a sorption overshoot in a later period. EVA showed Fickian transport at 60°C and anomalous diffusion at a higher swelling temperature (70°C) with sigmoidal uptake behavior. An analysis of the diffusion coefficients and the Fourier transform infrared results showed that the diffusing molecules were different in the case of LDPE and EVA, and there were possible polymer–asphalt interactions. Differential scanning calorimetry and swelling studies showed that penetrant-induced crystallization affected the diffusion process in the case of LDPE. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Swelling behavior of NR/EPDM rubber blends under compression strain

The effect of different blend compositions of natural rubber (NR)/ethylene–propylene diene monomer rubber (EPDM) on the swelling behavior of that blend in motor oil under compression strain was investigated. The compression recovery of all blend ratios investigated had positive values at low applied compression values (3%). However, at high compression values (18 and 35%), the compression recovery had negative values. The lower weight uptake of motor oil was shown by the EPDM vulcanizate, whereas the 25/75 NR/EPDM blend showed the highest compression recovery. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3052–3057, 2001     

Swelling behavior and diffusion studies of high‐water‐retaining acrylamide/potassium methacrylate hydrogels

Poly(acrylamide‐co‐potassium methacrylate) hydrogels were prepared by free‐radical simultaneous polymerization with aqueous solutions of acrylamide (AAm) and potassium methacrylate (KMA) with a redox initiator. The copolymerization was performed with eight different compositions of KMA at a fixed concentration of oil‐soluble crosslinkers, including 1,4‐butanediol diacrylate and ethylene glycol dimethacrylate (EGDMA). For every composition of AAm/KMA copolymer, the percentage swelling, swelling equilibrium, and diffusion characteristics were investigated. The copolymers were further studied for deswelling properties. The power law relationships of the hydrogels were evaluated for variation in terms of saline concentration. The AAm/KMA copolymers were confirmed by IR spectroscopy. Thermal studies of hydrogels were performed with differential scanning calorimetry and thermogravimetric analysis. EGDMA was found to be a better crosslinker for obtaining higher swelling and deswelling properties for the AAm/KMA hydrogels. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1153–1164, 2005     

Swelling properties of chemically modified oil palm empty fruit bunch based polyurethane composites

In this study, the diffusion of various types of solvent in oil palm empty fruit bunch/polyurethane composites, produced from chemically modified empty fruit bunches, was investigated. The solubility parameters and polymer–solvent interaction parameters of the produced composites were determined. The void contents of the composites were also determined before swelling tests to eliminate the free solvent present in the system. From the results obtained, we found that the diffusion of the solvents was dependent on the compatible group available and the voids present in the system. The solubility parameters of the empty fruit bunch/polyurethane composites with different degrees of chemical modification were 11.6 and 11.7 (cal/cm^?3)^1/2. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

有机介质中聚丙烯酸钠/SBR共混型WSR的溶胀性能

研究了兼具双亲性和膨胀性吸水膨胀橡胶对有机溶剂的吸收性能，测定了该吸水膨胀橡胶中有机相的溶解度参数，研究了吸水树脂等无机相对吸水膨胀橡胶在有机溶剂中最大溶胀度的影响。     

丙烯酸酯橡胶耐有机溶剂及耐油性的研究

采用平衡溶胀法测定了日本瑞翁公司生产的活氯型丙烯酸酯橡胶(AR840)在24种不同有机溶剂中的溶胀行为,得到了AR840的一维溶解度参数值,其范围在18～23(MPa)1/2之间.进一步用汉森三维溶解度参数软件(HSPiP)对溶胀数据进行分析研究,得到AR840三维溶解度参数值,色散分量(δd)、极性分量(δp)和氢键...     

Swelling behavior of pervaporation membranes in ethanol–water mixtures

Novel hydrophobic composite membranes made of crosslinked poly(dimethylsiloxane) and poly(methyl hydrogen siloxane) (PDMS–PMHS) with various amounts of catalyst were prepared. Pervaporation experiments with water–ethanol mixtures revealed that an optimum ratio of catalyst to polymer base existed. Both swelling behavior and dynamic–mechanical properties of these silicone films were studied. The swelling experiments in different mixtures of ethanol and water determined that ethanol is preferentially sorbed and that the membranes are only capable to absorb a limited quantity of solvent. Equilibrium swelling data were also used in combination with the analysis of the viscoelastic relaxation of the swollen samples to obtain the dependence of the dynamic–mechanical properties of the silicone films on the quantity of permeants sorbed into the membrane. It was observed that the permselective parameters were related with the mobility of the chains and the free volume. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1424–1433, 2000     

不同比例甲醇汽油对橡胶的溶胀影响研究

研究了丁腈橡胶(NBR)、氟橡胶(FKM)及氢化丁腈橡胶(HNBR)等三种典型橡胶在不同比例甲醇汽油中的理化性能与机械性能变化,并与乙醇汽油体系的溶胀进行了对比研究。实验结果表明:NBR在不同甲醇比例的浸泡体系中,尺寸、质量及体积变化率均小于6%,且尺寸变化率最小,基本维持在3%以下;溶胀后NBR的机械性能下降显著。FKM各项理化性能及机械性能在汽油中的变化均最小,在M30甲醇汽油体系中最大,且随着时间延长,其理化性能变化逐渐增大,而机械性能则无明显变化;在相同条件下,FKM的理化性能及机械性能变化均大于NBR与HNBR,而NBR与HNBR的变化趋势基本一致;NBR在甲醇汽油中的溶胀程度与其在乙醇汽油中基本相当。     

Formation of microporous polymeric materials by microemulsion radiation polymerization of butyl acrylate

A microemulsion system composed of butyl acrylate (BA) and water with a mixture of sodium 12‐acryloxy‐9‐octadecenate (SAO) and octylphenoxypoly(ethoxyethanol) as an emulsifier was initiated by γ‐ray radiation at room temperature to polymerize and produce microporous polymeric materials. The morphology and swelling characteristics of the resulting polymeric materials were studied. It was found that they strongly depended on the composition (water content, crosslinker content, emulsifier content) of the precursor microemulsions. In addition, the swelling properties of the polymer so prepared were found to be sensitive to the pH of the swelling medium. The change in swelling behaviors of the polymeric materials is discussed in terms of the polyelectrolyte effect exhibited by the polymerized anionic emulsifier SAO. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1989–1993, 2000     

Solubility of binary liquid mixtures in polymeric materials

Experimental data on the permeation of binary mixtures through polymeric materials show that liquid mixtures can exhibit large, positive synergistic rates. As the permeation rate depends on both solubility and the diffusion coefficient, the existence of a maximum in the steady-state permeation rate vs. the composition curve could be due to an increase in solubility and/or diffusion coefficient. In this study, a theoretical model based on the Flory-Huggins equation was developed to predict the solubility of binary liquid mixtures in polymers. The equation has four adjustable parameters that can be determined from solubilities of pure liquids in the polymer and the vapor-liquid equilibrium data for the binary liquid mixture. The model was tested for two binary liquid mixture/polymer systems. The predicted values of solubilities are close to the experimental data. © 1993 John Wiley & Sons, Inc.     

Swelling kinetics of linseed oil‐based polymers

Kinetics of swelling and sorption behavior of copolymers (based on linseed oil, styrene, divinylbenzene, and acrylic acid via cationic and thermal polymerization) is studied in tetrahydrofuran (THF) at different temperatures. The values of n in the transport equation are found to be below 0.4, showing non‐Fickian or pseudo‐Fickian transport in the polymers. The dependence of diffusion coefficient on the composition and temperature has also been studied for the linseed oil‐based polymers. The diffusion coefficient in cationic samples decreases with an increase in the oil contents in the samples. In case of thermal samples, the diffusion coefficient first increases up to 30% oil contents and then decreases. The diffusion coefficient decreases with an increase in temperature for all of the linseed oil polymer samples. The sorption coefficient increases with an increase in the oil contents for all samples. The crosslink density (calculated from the THF swelling) ranges from 20.16 to 92.34 × 10⁶ mol/cm³ for cationic samples and 20.62 to 86.01 × 10⁶ mol/cm³ for thermal samples. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Swelling Properties of Chemically Crosslinked Poly(acrylamide-co-maleic acid) Hydrogels

ABSTRACT

Chemically crosslinked poly(acrylamide-co-maleic acid) [poly(AAm-co-MA)] hydrogels were prepared by simultaneous free radical copolymerization of acrylamide (AAm) with maleic acid (MA) in presence of di or tri functional crosslinking agents using ammonium persulfate-N,N,N′,N′-tetramethylethylenediamine (APS-TMEDA) redox-initiating system. The poly(AAm-co-MA) hydrogels formation was confirmed by IR studies. The influence of crosslinkers such as N,N′-methylene-bis-acrylamide (MBA) and 2,4,6-triallyloxy-1,3,5-triazine (TATA) on swelling/de-swelling characteristics were studied in detail for poly(AAm-co-MA) hydrogels containing different amounts of maleic acid. The present investigation also deals with the influence of concentration of crosslinker and initiator on the swelling behavior of poly(AAM-co-MA) hydrogels. The effect of various salts on swelling capacity was studied. In addition, the effect of simulated biological fluids and pH solutions on the swelling of hydrogels was also studied in detail.     

非离子型凝胶球在水中的溶胀行为

以过硫酸铵和N,N,N',N',-四甲基乙二胺氧化-还原体系引发丙烯酰胺聚合,制备球状非离子型水凝胶.利用带刻度的显微镜记录了凝胶球在水中的溶胀扩散过程,采用Tanaka-Fillmore凝胶溶胀动力学模型进行数学处理,得到凝胶网络扩散系数.在此基础上,进一步考察了交联剂、引发剂、单体浓度对凝胶网络扩散系数的影响,结果表明:随着交联剂用量的提高,扩散系数先变小后增大;增加引发剂﹑单体浓度,扩散系数均增大.对凝胶网络扩散系数-温度理论模型进行修正,更加符合实验结果,可用于凝胶网络扩散系数的预测.     

Swelling behavior and determination of diffusion characteristics of acrylamide–acrylic acid hydrogels

In this study, a random copolymer of acylamide and acrylic acid [poly(AAm‐co‐AA)] was prepared by a redox copolymerization method of their aqueous solutions. The effects of initial AAm/AA mole ratio, PEG 4000 content, and N,N′‐methylenebisacrylamide concentration on swelling behavior were investigated in water. Average molecular weights between crosslinks, percentage swelling, swelling equilibrium values, and diffusion/swelling characteristics (i.e., the structure of network constant, the type of diffusion, the initial swelling rate, swelling rate constant) were evaluated for every hydrogel systems. The hydrogels showed mass swelling capabilities in the range 789–1040% (for AAm/AA hydrogels), 769–930% (for AAm/AA hydrogels in the presence of PEG 4000), and 716–1040% (for AAm/AA hydrogels containing different concentrations of the crosslinker). The swelling capabilities of the hydrogels decreased with the increasing AA, PEG 4000, and crosslinker concentrations. The diffusion of water into AAm/AA hydrogels was found to be a non‐Fickian type. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1289–1293, 2004