氯化聚乙烯双亲性接枝聚合物的合成与表征（Ⅰ）

采用“架桥剂”法,以马来酸酐（ＭＡＮ）为“架桥剂”,使氯化聚乙烯（ＣＰＥ）主链上接上一定数量的酸酐基团,然后利用接上去的酸酐基团与ＰＭＭＡ－ＯＨ、ＰＥＧ、ＰＰＧ、ＰＴＭＧ等反应合成了主链疏水、支链亲水或疏水的双亲性聚合物,并用ＩＲ、ＴＧ－ＤＴＡ进行了表征。     

A novel radial orientation treatment of nematic liquid crystals using magnetic field lines with permanent magnet and applying the assisted electric field

Recently, there has been considerable research on optical devices, such as liquid crystal (LC) lenses and special optical plates, using LCs. In such devices, relatively small LC cells are frequently used, or unique LC orientations are required. As an LC orientation process, we focused on the LC director's orientation induced by the magnetic force line distribution of a small neodymium magnet. We propose a simple method for obtaining radial orientation, which is rather difficult to obtain using the ordinary rubbing method. The initial orientation in the LC cell is a vertical orientation cell with almost zero azimuth anchoring. With the proposed method, the reorientation process is performed with an assisting electric field and a small permanent magnet, unlike the conventional magnetic field orientation process that requires a large electromagnet. Furthermore, a polymer stabilization treatment is used to fix the obtained radial orientation pattern in the LC cell. After the treatment, the applying voltage can control the tilt angle of the director in weak polymer treatment, and a completely fixed orientation pattern can be obtained that in strong.     

Strategies for electrosynthesis of poly(vinylbenzyltrimethylammonium chloride) and composite films

Poly(vinylbenzyl trimethyl ammonium chloride) (PVT) exhibits functional properties, which have generated interest in the fabrication of PVT and composite films. New electrochemical strategies have been utilized for the deposition of PVT-zirconia composites. The problems, related to the electrodeposition of strong polyelectrolytes, such as PVT, were addressed by the development of charge compensation mechanisms. The deposition strategies involved electrophoretic cathodic deposition (EPD) of PVT and EPD or electrochemical synthesis of zirconia. The proof of concept investigations involved deposition yield studies under different conditions, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and electron microscopy studies. The electrochemical strategies can be used for electrodeposition of various composites, utilizing the properties of functional polymers and inorganic materials.     

Homopolymer Nanolithography

Future progress in nanoscience and nanotechnology necessitates further development of versatile, labor‐, and cost‐efficient surface patterning strategies. A new approach to nanopatterning is reported, which utilizes surface segregation of a smooth layer of an end‐grafted homopolymer in a poor solvent. The variation in polymer grafting density yields a range of surface nanostructures, including randomly organized pinned spherical micelles, worm‐like structures, networks, and porous films. The capability to use the polymer patterns for site‐specific deposition of small molecules, polymers, or nanoparticles is shown. This versatile strategy enables patterning of curved surfaces with direct access to the substrate and no need in changing polymer composition to realize different surface patterns.     

Engineered microparticles based on drug–polymer coprecipitates for ocular-controlled delivery of Ciprofloxacin: influence of technological parameters

Abstract

Ciprofloxacin is a drug active against a broad spectrum of aerobic Gram-positive and Gram-negative bacteria, for the therapy of ocular infections. It requires frequent administrations owing to rapid ocular clearance and it is a good candidate for ocular controlled release formulations. The preparation of such drug release systems is still a challenge. Ionic interactions between ciprofloxacin and the polyelectrolytes chondroitin sulfate or lambda carrageenan result in coprecipitates that can act as microparticulate controlled release systems from which the drug is released after being displaced by the medium’s ions. In some formulations, Carbopol was added to improve the mucoadhesive properties. The aim of this research was the study of the influence of the technological parameters of the preparation method of coprecipitates on their particle size, with the goal of achieving particles engineered with a size suitable for the ocular administration. Technological parameters taken into account were: concentration of drug and polymer solutions utilized for the preparation of interaction products, possible use of surfactants (kind and concentration), temperature of the solutions and stirring during the process of preparation of the coprecipitates. Preliminary stability study tests were carried out to further characterize the leader formulation. Particle size in suspensions for ocular drug delivery is a critical parameter influencing the quality of the formulation. The results obtained from this study show that chondroitin sulfate coprecipitates present the best characteristics in terms of particle size suitable for ocular administration. A further improvement of the particle size characteristics has been obtained with the addition of surfactants.     

聚砜酰胺基单聚合物复合材料的热性能及降解动力学

采用热重分析对作为耐高温材料使用的聚砜酰胺基单聚合物复合材料(PSA SPCs)进行热性能研究。通过计算积分程序分解温度(IPDT)和温度指数Ts分别评价材料的热稳定性和长期使用温度,通过计算温度指数Tzg来表征耐热性能。PSA SPCs的IPDT、Ts以及Tzg分别为1305℃,248℃和255℃,而PSA树脂材料相对应的参数值依次是1162℃,243℃和244℃,表明PSA SPCs的热性能优于PSA树脂材料。采用不同升温速率,分别用Flynn-Wall-Ozawa法和Kissenger法研究其热降解动力学,计算得到反应活化能(Ea)分别为152.26 k J/mol,146.85 k J/mol,优于PSA树脂材料的Ea值(133.54 k J/mol,127.88 k J/mol)。