N‐(hydroxymethyl) acrylamide as a multifunctional finish to cotton and a tether for grafting methacrylamide for biocidal coatings

N‐(hydroxymethyl) acrylamide (NMA) was immobilized on cotton surfaces through etherification, and then methacrylamide (MA) was grafted onto the treated surface. The coatings were characterized by ATR‐IR spectroscopy and were rendered biocidal upon exposure to dilute household bleach. The treated fabrics were challenged with Gram‐negative and Gram‐positive bacteria; both NMA and NMA/MA‐treated fabrics inactivated about 8 logs of Escherichia coli O157:H7 and Staphylococcus aureus within only 5 min of contact time. The coatings were also quite stable toward ultraviolet (UVA) light exposure and repeated laundering. Moreover, a substantial improvement in wrinkle recovery angle was obtained for the NMA/MA‐treated fabrics. The new acyclic acrylamide N‐halamine coating should be less expensive to produce and use than previous cyclic N‐halamine coatings developed in these laboratories. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Molecular modeling of physical aging in epoxy polymers

Epoxy resins are often exposed to prolonged periods of sub‐T_g temperatures which cause physical aging to occur. Because physical aging can compromise the performance of epoxies and their composites and because experimental techniques cannot provide all of the necessary physical insight that is needed to fully understand physical aging, efficient computational approaches to predict the effects of physical aging on thermomechanical properties are needed. In the current study, a new method is developed to efficiently establish molecular models of epoxy resins that represent the corresponding molecular structure at specific aging times. Although this approach does not simulate the physical aging process directly, it is useful in establishing molecular models that resemble physically aged states of epoxies. Such models are useful for predicting the thermomechanical properties of aged epoxy resins to facilitate the design of durable engineering structures. For demonstration purposes, the developed method is applied to an EPON 862/diethylene toluene diamine epoxy system for three different crosslink densities. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Dual‐layer PBI/P84 hollow fibers for pervaporation dehydration of acetone

Acetone dehydration via pervaporation is challenging, because acetone and water have close molecular sizes, and acetone has a much higher vapor pressure than water. Acetone is also a powerful solvent, which dissolves or swells most polymers. We have developed novel polybenzimidazole/BTDA‐TDI/MDI (PBI/P84) dual‐layer hollow fibers for pervaporation dehydration of acetone for industrial and biofuel separations. Both thermal and chemical crosslinking modifications were applied to the membranes to investigate their effectiveness to overcome acetone‐induced swelling. Thermal treatment can effectively enhance separation performance, but performance stability can only be achieved through the crosslinking modification of PBI. Crosslinking by p‐xylene dichloride followed by a thermal treatment above 250°C show significant effectiveness to improve and stabilize pervaporation performance. The fractional free volume of the PBI selective layer reduces from 3.27 to 1.98% and 1.33%, respectively, after thermal treatment and a combination of chemical/thermal crosslinking modifications characterized by positron annihilation spectroscopy. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

用于防水涂料的自交联丙烯酸弹性乳液

：以N-羟甲基丙烯酰胺（NMA）为自交联单体,SDS/OP-10为复合乳化剂,过硫酸铵（APS）为引发剂,采用半连续种子乳液聚合工艺和正交试验方法研究了不同用量的引发剂、乳化剂、交联单体和反应温度对弹性丙烯酸酯乳液性能的影响.结果表明：当APS、复合乳化剂和NMA用量分别为单体总量的0.7％、3％和1％,聚合温度为75 ℃时,可以制备出凝聚率低、转化率高、黏度和交联度适中的自交联丙烯酸弹性乳液;以其为基料与水泥复合制备的防水涂料涂膜吸水率较低,拉伸强度和断裂伸长率达到了国家标准以上.     

交联剂Ec—1对TKA—1涂膜性能影响的研究

本文研究环氧型外交联剂ＥＣ—１对改性羽毛蛋白涂饰剂ＴＫＡ—１涂膜力学性能，耐水性能，热学性能和表面形态的影响。使用ＥＣ—１可以使ＴＫＡ—１涂层干擦达到４～５级，湿擦达到３～４级，改性羽毛蛋白涂饰剂也可以用于抛光涂饰。     

Evaluation of Injectable Composite Material Comprising Biphasic Bone Substitutes and Crosslinked Collagen

Bone tissue engineering has emerged as a promising approach to regenerate bone tissue, and injectable biomaterials have shown potential for bone regeneration applications due to their ease of administration and ability to fill irregularly shaped defects. This study aims to develop and characterize an injectable composite material comprising biphasic bone substitutes (BBS) and crosslinked porcine collagen type I for bone regeneration applications. The collagen is crosslinked via a UVA-riboflavin crosslinking strategy and evaluated by testing the physicochemical properties, including the rheological behavior, dynamic storage modulus (G′) and loss modulus (G″), and in vitro degradation process. The results show that the crosslinked collagen (xCol) exhibits suitable physicochemical properties for injectability and improved viscoelasticity and degradation resistance. Furthermore, xCol is then combined with BBS in a predetermined ratio, obtaining the injectable composite material. The biocompatibility of the materials is evaluated in vitro by XTT and BrdU assays on fibroblasts and preosteoblasts. The results demonstrate that the composite material is biocompatible and supporting pre-osteoblasts proliferation. In conclusion, the injectable composite material BBS-xCol has promising physiochemical and biological properties for bone regeneration applications. Further studies are warranted to evaluate its efficacy in vivo and optimize its composition for clinical translation.     

自由基引发活性聚碳硅烷交联及其在制备SiC纤维中的应用

在基于先驱体聚碳硅烷转化制备SiC陶瓷纤维过程中, 交联过程是保持纤维形貌和提高陶瓷产率的必要条件。本研究以含丙烯酸酯基的聚碳硅烷(A-PCS)为原料, 通过引入自由基热引发剂在热解升温过程中实现原料的交联成型。采用红外光谱仪(FT-IR)和差示扫描量热仪(DSC)研究了引发剂含量对A-PCS交联程度、交联速率以及热降解速率的影响规律; 采用热失重(TG)、元素分析仪和X射线衍射仪(XRD)分析了陶瓷产率、陶瓷产物组成以及无定形态随温度的变化。研究结果表明: 加入自由基热引发剂可提高A-PCS中的丙烯酸酯基的交联速率, 减少交联阶段的热失重; 将质量百分比为1%自由基热引发剂的A-PCS以5 ℃/min升至250 ℃时, 丙烯酸酯基反应完全, 1500 ℃的陶瓷产率为69.5%; 通过静电纺丝加工工艺可获得直径介于2~5 μm的A-PCS原丝, 并通过后续升温热解转化为SiC纤维; 所得SiC纤维形貌规整、无熔并现象, 且随着热解温度的升高从无定形态向结晶形态转变。     

半纤维素的提取及其温敏性水凝胶的制备

以采用稀碱抽提法从植物残料中提取的半纤维素为原料,通过化学交联法,自由基聚合将单体接枝到半纤维素链上,并交联温敏性单体,促使形成共聚交联网络结构,得到温度敏感性水凝胶。通过物理交联法,半纤维素与壳聚糖物理交联,制备半纤维素基水凝胶。采用交联度测定、溶胀动力学研究、红外光谱、差示量热等手段对化学交联和物理交联两种方法制得的半纤维素基水凝胶温度响应性能进行表征。结果表明:10%NaOH提取的半纤维素得率最高;化学交联法和物理交联法制得的半纤维素基水凝胶,都具有温度负响应特性,为温敏性水凝胶。作为当下较为热门材料,广泛应用于医疗、农业和生物组织工程材料等领域。     

A Crosslinked Polytetrahydrofuran‐Borate‐Based Polymer Electrolyte Enabling Wide‐Working‐Temperature‐Range Rechargeable Magnesium Batteries

A polymer‐based magnesium (Mg) electrolyte is vital for boosting the development of high‐safety and flexible Mg batteries by virtue of its enormous advantages, such as significantly improved safety, potentially high energy density, ease of fabrication, and structural flexibility. Herein, a novel polytetrahydrofuran‐borate‐based gel polymer electrolyte coupling with glass fiber is synthesized via an in situ crosslinking reaction of magnesium borohydride [Mg(BH₄)₂] and hydroxyl‐terminated polytetrahydrofuran. This gel polymer electrolyte exhibits reversible Mg plating/stripping performance, high Mg‐ion conductivity, and remarkable Mg‐ion transfer number. The Mo₆S₈/Mg batteries assembled with this gel polymer electrolyte not only work well at wide temperature range (?20 to 60 °C) but also display unprecedented improvements in safety issues without suffering from internal short‐circuit failure even after a cutting test. This in situ crosslinking approach toward exploiting the Mg‐polymer electrolyte provides a promising strategy for achieving large‐scale application of Mg‐metal batteries.     

The Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development

Collagen is the oldest and most abundant extracellular matrix protein that has found many applications in food, cosmetic, pharmaceutical, and biomedical industries. First, an overview of the family of collagens and their respective structures, conformation, and biosynthesis is provided. The advances and shortfalls of various collagen preparations (e.g., mammalian/marine extracted collagen, cell‐produced collagens, recombinant collagens, and collagen‐like peptides) and crosslinking technologies (e.g., chemical, physical, and biological) are then critically discussed. Subsequently, an array of structural, thermal, mechanical, biochemical, and biological assays is examined, which are developed to analyze and characterize collagenous structures. Lastly, a comprehensive review is provided on how advances in engineering, chemistry, and biology have enabled the development of bioactive, 3D structures (e.g., tissue grafts, biomaterials, cell‐assembled tissue equivalents) that closely imitate native supramolecular assemblies and have the capacity to deliver in a localized and sustained manner viable cell populations and/or bioactive/therapeutic molecules. Clearly, collagens have a long history in both evolution and biotechnology and continue to offer both challenges and exciting opportunities in regenerative medicine as nature's biomaterial of choice.