ASA树脂制备方法的新进展

探讨了ASA树脂制备过程中,工艺上的一些关键问题和解决的方法,包括制备大粒径丙烯酸丁酯胶乳的各种附聚方法、共聚过程中活性单体的选择以及对接枝率的影响等。     

太阳能电池生产项目污染产生与处理措施

太阳能电池是使用硅片经过表面处理、扩散、硅沉积、电极印刷、焊接等工序制备。该过程中产生一定的酸性废气、有机废气、氨气,以及酸碱废水、有机废水等;文章介绍了太阳能电池的生产工艺流程,论述了大气、水污染物产生情况及其处理措施;并对太阳能电池生产中废气、废水污染物特点及相应的污染处理工艺进行了探讨并提出相关建议。     

气固相法生产氯化聚氯乙烯树脂的研究进展

着重介绍了气固相法制备氯化聚氯乙烯（CPVC）树脂的研究进展,对该法制备CPVC的生产工艺、反应机理以及反应动力学进行了阐述,其中生产工艺主要包括热引发氯化、光引发氯化和等离子体引发氯化等。     

载铜蒙脱土对聚氯乙烯材料阻燃性能的研究

通过离子交换反应将铜离子负载在无机层状蒙脱土上,采用十六烷基三甲基溴化铵对载铜蒙脱土进行有机改性,并将其作为阻燃剂添加到软质聚氯乙烯(PVC)材料中。利用X射线衍射对PVC/有机改性载铜蒙脱土的结构进行表征。结果表明,PVC分子链插层进入有机改性载铜蒙脱土层间形成插层型结构,且蒙脱土的层间距达到3.69 nm。热重分析、极限氧指数、垂直燃烧和烟密度测试结果表明,有机改性载铜蒙脱土有效改善了PVC的热稳定性,大幅提高了其阻燃性能。载铜蒙脱土的用量仅为PVC用量的3 %时,垂直燃烧即可达到V0级。     

Peptide-Mimicking Poly(2-oxazoline)s Displaying Potent Antimicrobial Properties

Poly(2-oxazoline)s have excellent biocompatibility and have been used as FDA-approved indirect food additives. The inert property of the hydrophilic poly(2-oxazoline)s suggests them as promising substitutes for poly(ethylene glycol) (PEG) in various applications such as anti-biofouling agents. It was recently reported that poly(2-oxazoline)s themselves have antimicrobial properties as synthetic mimics of host defense peptides. These studies revealed the bioactive properties of poly(2-oxazoline)s as a new class of functional peptide mimics, by mimicking host defense peptides to display potent and selective antimicrobial activities against methicillin-resistant Staphylococcus aureus both in vitro and in vivo, without concerns about antimicrobial resistance. The high structural diversity, facile synthesis, and potent and tunable antimicrobial properties underscore the great potential of poly(2-oxazoline)s as a class of novel antimicrobial agents in dealing with drug-resistant microbial infections and antimicrobial resistance.     

Effect of silane treated fly ash on physico-mechanical,morphological, and thermal properties of recycled poly(vinyl chloride) composites

The silane treatment on properties of fly ash (FA) and development of its composite using recycled poly(vinyl chloride) (r-PVC) material retrieve from waste wires and cable insulation are investigated in this work. The use of (3-aminopropyl)triethoxysilane was employed as a coupling agent with some other essential additives. The composites sheet was prepared by means of the melt mixing process and go along with the compression molding process. The superior properties on compatibility between silane-modified FA (FA(Si)) and r-PVC were successfully studied using rheological, thermomechanical, morphological, and water absorption analysis. Primary analysis of r-PVC and FA was employed using Fourier transform infrared spectroscopy analysis. The thermal stability of composites was stable up to 187°C. In addition, significant enhancement on tensile strength as well as young's modulus of composite as compared to untreated r-PVC/FA composites. Morphological properties of silane treated FA based composites presented the good distribution and excellent uniformity with higher wettability of FA particles within r-PVC matrix. The water absorption test showed decrease in water absorption with increase silane treatment concentration FA in the r-PVC matrix. It was remarkable to note that silane treated FA can be prepared as a composite using r-PVC matrix with further modified properties.     

Fabrication of poly(PEGMA) surface with controllable thickness gradient and its mediation on the gradient adhesion of cells

The gradient surface shows enormous potential in the development of tissue engineering, biosensor, microfluidic control, and particle sorting. In this work, a poly(polyethyleneglycol methacrylate) (poly(PEGMA)) gradient surface was prepared through surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-AGRET ATRP). The effect of various parameters on the thickness growth of poly(PEGMA) film were analyzed, among which the excessive reducing agent was utmost important. The reducing agents supported the regeneration of Cu^I and eliminated the disturbance of air, maintaining the "living polymerization" of poly(PEGMA) up to 73.1 nm under tested conditions. The physicochemical properties of the fabricated surfaces were characterized by ellipsometry, X-ray photoelectron spectroscopy, water contact angle. The thickness slope of gradient poly(PEGMA) was controllable in a nanoscale range. The gradient surface was further grafted with CRGD (Cys-Arg-Gly-Asp) peptides onto the poly(PEGMA-co-[glycidyl methacrylate]) blocks via the ring-opening reaction between epoxy and amino groups, which showed a gradient change in water contact angle and adhesion of endothelial cells.     

Tuning of shear thickening behavior and elastic strength of polyvinylidene fluoride via doping of ZnO-graphene

ZnO rice like nonarchitects are grafted on the graphene carbon core via a rapid microwave synthesis route. The prepared grafted systems are characterized via XRD, SEM, RAMAN, and XPS to examined the structural and morphological parameters. Zinc oxide grafted graphene sheets (ZnO-G) are further doped in β-phase of polyvinylidene fluoride (PVDF) to prepare the polymer nanocomposites (PNCs) via mixed solvent approach (THF/DMF). β-phase confirmation of PVDF PNCs is done by FTIR studies. It is observed that ZnO-G filler enhances the β-phase content in the PNCs. Non-doped PVDF and PNCs are further studied for rheological behavior under the shear rate of 1–100 s⁻¹. Doping of ZnO-G dopant to the PVDF matrix changes its discontinuous shear thickening (DST) behavior to continues shear thickening behavior (CST). Hydrocluster formation and their interaction with the dopant could be the reason for this striking DST to CST behavioral change. Strain amplitude sweep (10⁻³% -10%) oscillatory test reveals that the PNCs shows extended linear viscoelastic region with high elastic modulus and lower viscous modulus. Effective shear thickening behavior and strong elastic strength of these PNCs present their candidature for various fields including mechanical and soft body armor applications.     

Facile Fabrication of Poly(vinyl alcohol)/Polyquaternium-10 (PVA/PQ-10) Anion Exchange Membrane with Semi-Interpenetrating Network

Anion exchange membranes (AEMs) are one of the core components of AEM fuel cells. A series of poly(vinyl alcohol)/polyquaternium-10 (PVA/PQ-10) AEMs with semi-interpenetrating networks (s-IPNs) are prepared by a simple solution-casting method using glutaraldehyde (GA) as a cross-linking agent. Subsequently, the prepared PVA/PQ-10 cross-linked membranes are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, mechanical analysis, water uptake and swelling ratio tests, ion exchange capacity (IEC) tests, ionic conductivity measurements, and oxidative/alkaline stability tests. The effects of the mass ratio of PVA and PQ-10 and the amount of cross-linking agent GA on the performance of the PVA/PQ-10 cross-linked membranes are systematically explored. The results show that the cross-linked PVA/PQ-10 AEMs have high IEC and low water uptake and swelling ratio, and its maximum ionic conductivity can reach 79.37 mS cm^–1 at 80 °C. In addition, the PVA/PQ-10 cross-linked membrane has good oxidative and alkaline stability under optimal preparation conditions. These results may provide valuable insights toward more effective scheme designs and new, simple preparation methods for AEMs with s-IPN structures.