Study of the composition effect of glass ceramic and silver on poly(vinyl butyral) thermal degradation with thermogravimetric analysis

The thermal degradation of poly(vinyl butyral) (PVB)/glass ceramic, PVB/Ag, and PVB/glass ceramic/Ag composites was investigated with thermogravimetric analysis in nitrogen and air. Thermogravimetric data revealed that the compositions of both inorganic materials in air could greatly influence the thermal degradation of PVB. The degradation reactions of PVB/ceramic and PVB/Ag composites began earlier and accelerated rapidly at lower temperatures. The overall degradation period was obviously shortened for the thermal degradation of PVB/Ag in air, whereas a longer time was required for the PVB/ceramic composite than for PVB. Moreover, dual effects of ceramic and Ag on the thermal degradation of PVB were observed for PVB/ceramic/Ag composites. In addition, the catalytic effects of ceramic and Ag on the degradation reaction of PVB in air were verified with a kinetic analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2142–2149, 2004     

Eco‐friendly durable press finishing of cellulose‐containing fabrics

To impart easy‐care properties to cellulose‐containing fabrics along with avoiding any harmful effects of formaldehyde on both the health and the environment, attempts have been made to use citric acid (CA) as an ester crosslinking agent along with different catalytic systems in the absence and presence of certain additives. Further, fixation conditions, type of crosslinking agent, as well as type of substrate have been studied. Results revealed that the enhancement in carboxyl content, performance properties, and the decrease in tear strength (TS) as well as in whiteness indices (WI) of the finished fabric samples were increased by increasing CA concentration up to 80 g/L and by raising thermofixation temperature from 140 up to 180°C for 90 s. Inclusion of triethanolamine hydrochloride (TEA. HCl), decreased the carboxyl content, TS, color strength K/S, as well as oily stain release rating (SRR) of the finished fabric samples along with an increase in bound nitrogen (%N), wrinkle recovery angle WRA, and an improvement in WI without affecting the durable press rating (DP). Within the range examined (0–30 g/L), increasing PEG‐600 concentration improved the wet resiliency, TS, as well as WI properties of the finished samples. Increasing DMDHEU ratio in the CA/DMDHEU crosslinking system gave rise to an increase in %N, WRA (dry and wet), DP, as well as in free CH₂O of finished fabrics, along with a slight improvement in WI values. On the other hand, the TS, carboxyl content, K/S, SRR values of the finished fabric samples were lower at a higher DMDHEU ratio. Increase in carboxyl content, %N, WRA (dry and wet), DP and SRR, as well as extent of post dyeing (K/S) of the treated fabric samples upon using different ester crosslinking agents followed the descending order: citric acid > pyromellitic dianhydride. The opposite holds true for the TS, and WI values. Among the esterifying catalysts used, and for a given set of finishing conditions, NaH₂PO₂ · H₂O proved to be the most effective one, and the following order of effectiveness may be drawn: NaH₂PO₂ · H₂O > K₂HPO₄ > Na₃–citrate > Na₂–tartrate. Inclusion of silicone softener in the finishing formulation brought about an improvement in softeness degree, WRA, %N, DP, TS as well as K/S values along with a decrease in carboxyl content, SRR, and WI values of the treated fabric samples, regardless of the used silicone softener.The performance properties of the finished fabric samples were determined by the type and nature of the substrate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2243–2253, 2002     

Synthesis,characterization, and thermal properties of phosphorus‐containing,wholly aromatic thermotropic copolyesters

A series of phosphorus‐containing, wholly aromatic thermotropic copolyesters from acetylated 2‐(6‐oxide‐6H‐dibenz〈c,e〉〈1,2〉oxa phosphorin‐6‐yl)‐1,4‐dihydroxy phenylene, p‐acetoxybenzoic acid, terephthalic acid, and isophthalic acid were prepared by melting polycondensation. The structure and basic properties of the polymers, such as the glass‐transition temperature (T_g), melting temperature (T_m), thermal stability, crystallinity, and liquid crystallinity, were investigated with Fourier transform infrared, elemental analysis, differential scanning calorimetry (DSC), thermogravimetric analysis, wide‐angle X‐ray diffraction, and hot‐stage polarizing optical microscopy. The copolyesters had relatively high T_g values ranging from 183 to 192°C. The T_m values obtained from DSC curves for samples P‐20 and P‐25 were 290 and 287°C, respectively (where the number in the sample name indicates the molar fraction of the phosphorus‐containing monomer in the reactants). The initial flow temperatures of other samples observed with hot‐stage polarizing microscopy were 271–290°C. The 5% degradation temperatures in nitrogen ranged from 431 to 462°C, and the char yields at 640°C were 41–52%. All the copolyesters, except P‐40, were thermotropic and nematic. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1278–1284, 2002     

Poly(etherimide)/montmorillonite nanocomposites prepared by melt intercalation

A novel aromatic amine organo‐modifier synthesized in our previous work was used to treat montmorillonite (MMT) and the organo‐modified MMT was used to prepare poly(etherimide) (PEI)/MMT nanocomposites by a melt intercalation method. MMT treated by this amine exhibited large layer‐to‐layer spacing and a high ion‐exchange ratio (>95%). The nanocomposites were characterized with X‐ray diffraction (XRD), transmission electron microscopy (TEM), dynamic mechanical analysis, a universal tester, thermogravimetric analysis, and by differential scanning calorimetry. The results of XRD and TEM showed that the nanocomposites formed exfoliated structures even when the MMT content was 10 wt %. When the MMT content was below 3 wt %, the PEI/MMT nanocomposites were strengthened and toughened at the same time. The nanocomposites also showed marked decreases in coefficient of thermal expansion and solvent uptake. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1857–1863, 2003     

2,6-二氟苯甲酸合成工艺研究

为优化2,6-二氟苯甲酸(DFBA)的合成工艺,以2,6-二氯苯腈(DCBN)和氟化钾为原料,N,N-二甲基酰胺(DMF)为溶剂,在聚醚类催化剂A的催化下氟代合成中间体2,6-二氟苯腈,然后中间体在碱性条件下水解制得(DFBA).试验结果表明,合成DFBN的最佳条件为:DCBN在DMF中的质量浓度为0.38g/mL,KF的量为DCBN的量的2.3～2.4倍,反应时间10 h,最高收率93.5%;合成DFBA时,以质量分数为20%的NaOH为介质,反应时间9 h,收率≥92%.收率93.5%,纯度99.7%.该工艺收率高、三废排放少,可节省成本,有望工业推广.     

Muscular fatigue and maximum endurance time assessment for male and female industrial workers

A single arm pushing experiment was conducted in an electronic factory in Yantai, China to assess muscular fatigue using the theoretical models of muscular strength and maximum endurance time (MET) developed by Ma et al. (2009). Seventy seven workers, including 38 males and 39 females, participated in the study. The muscular strength of pushing was measured after the subject pushed a stick, with a force of 2.5 kgf, for 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 min. Fatigue rate was determined based on a regression approach. In addition to the theoretical model, the MET for such a pushing task was also determined using four empirical models in the literature. The results indicated that females were more resistant to muscular fatigue than males in the pushing task. The results of the muscular strength prediction show that the predictability of the muscular strength model is acceptable. The prediction errors for muscular strength for female subjects were significantly lower than those of the male subjects. The predicted MET using the theoretical model, with a group constant k, was highly correlated with those using the empirical models compared in the current study.     

基于HEIV模型的摄像机一维标定

多摄像机系统广泛应用于文化创意产业,其高精度标定是迫切需要解决的一个关键问题. 新近出现的摄像机一维标定方法能够克服标定物自身遮挡,特别适合标定多摄像机系统. 然而,现有的摄像机一维标定研究主要集中在降低一维标定物的运动约束,而标定精度较低的问题未受到应有的关注. 本文提出一种基于变量含异质噪声 （Heteroscedastic error-in-variables,HEIV）模型的高精度摄像机一维标定方法. 首先,推导出摄像机一维标定的计算模型;其次,利用该计算模型详细分析了一维标定中的噪声,得出摄像机一维标定可以视为一个HEIV问题的结论;最后给出了基于HEIV模型的摄像机一维标定算法. 与现有的算法相比,该方法可以显著改善一维标定的精度,并且受初始值影响小,收敛速度快. 实验结果验证了该方法的正确性和可行性.     

Moisture Distribution and Dewatering Efficiency for Wet Materials

This review paper summarizes current research efforts toward a comprehensive view of wet material dewatering, considering the binding energy as the strength to hold water, and rupture energy given to remove moisture from materials.     

Antimicrobial protection of cotton and cotton/polyester fabrics by radiation and thermal treatments. I. Effect of ZnO formulation on the mechanical and dyeing properties

Cotton and cotton/polyester fabrics were treated against microbial attack by applying a formulation based essentially on ZnO under high‐energy radiation and thermal curing. To achieve the homogeneity and the reactivity of the treating formulation, a binder (Impron MTP) and a dispersing agent (Setamol WS) were used with ZnO. The antimicrobial property of the fabrics was evaluated, in terms of mechanical properties, by a soil burial test. Moreover, the effect of antimicrobial finishing on the dyeing properties in terms of color strength was investigated. It was found that the best composition that affords the best antimicrobial protection to cotton fabrics contains 2% ZnO, 2% binder, and 1% dispersing agents. For the cotton/polyester blend, the best results were achieved at the same conditions except the ZnO was 1%. It was found that the treatment under the effect of electron‐beam irradiation is better than that of gamma irradiation and thermal curing. The results showed that when the finishing process was carried out before dyeing with a reactive dye, it affects the color strength rather than performing the finishing after the dyeing process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1129–1137, 2003     

Rheological properties of ethylcellulose latex

Because of their large specific surface area, aqueous‐based pseudolatex systems of ethylcellulose can absorb large amounts of drugs. In addition, the stability of polymeric particles in biological fluids delays the release of the drug as in controlled drug delivery systems. The aim of the present study was to characterize the rheological properties of latex particles as a measure of their colloidal stability. Here, we report the effect of three variables: pH, electrolyte concentration, and temperature. The rheograms clearly show that the polymer suspensions displayed Bingham plastic behavior. Internal structuring of the latex was greatest at acid and natural pH values, particularly at the highest ionic strength. In acid solutions, only temperature appeared to play a fundamental role; both the shear stress corresponding to the onset of nonlinear viscoelasticity and the elastic modulus at all frequencies were higher at 37°C than those at room temperature. This is assumed to be a consequence of deformation of the polymer particles upon heating. The effect of ionic strength was noticeable only at the natural pH (pH ? 6.5). At high concentrations of sodium chloride, the particles aggregated because of the decrease in double layer repulsion, and as a result, the latex became structured and its elastic modulus subsequently increased. Interestingly, when the temperature was increased further, this structure presumably broke, down, at least partially, and the storage modulus was reduced. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 847–851, 2006