Nucleation kinetics and growth aspects of semi organic non‐linear optical bis thiourea cadmium acetate single crystals

Nucleation parameters such as metastable zone width, induction period and interfacial energy have been determined for the aqueous solution growth of bis thiourea cadmium acetate (BTCA) single crystals. Solubility of BTCA has been determined for various temperatures. Metastable zone width and induction period values have been estimated in order to optimize the growth parameters. The interfacial tension values derived from experimentally determined induction period are found to be comparable with theoretical values. Bulk crystals of BTCA have been grown using the optimized growth parameters. The grown crystals have been subjected to structural, optical and mechanical property studies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Formaldehyde-free flame retardant finishing of silk using a hydroxyl-functional organophosphorus oligomer

Flame retardancy is a desirable property for silk textiles, and it becomes necessity when silk textiles are for interior decorative use in building with public access. However, the flame retardant finishing technology available for silk has significant limitations. In this research, we studied the use of the combination of a hydroxyl-functional organophosphorus oligomer (HFPO) and 1,2,3,4-butanetetracarboxylic acid (BTCA) as a formaldehyde-free flame retardant finishing system for silk. When BTCA is applied to silk, most of BTCA reacts with the hydroxyl group on silk by single ester linkage. In the presence of HFPO, BTCA is able to bond HFPO onto silk by either a BTCA “bridge” between silk and HFPO or a BTCA-HFPO-BTCA cross-linkage between two silk protein molecules. We evaluated the flammability and physical properties of the silk fabric treated with HFPO and BTCA. The treated silk fabric demonstrated a high level of flame retardancy with modest loss in fabric tensile strength. The treated silk passed the vertical flammability test after 15 hand wash (HW) cycles. Increasing the HFPO concentration from 20% to 30% does not show significant improvement in the flame retardant performance of the treated silk. The thermal analysis data demonstrated that HFPO reduces silk's initial thermal decomposition temperature and promotes char formation.     

一种新的共发光体系──铽－钆（钪）－均苯四甲酸体系的研究和应用

本文研究发现铽与均苯四甲酸有强烈的荧光反应，并观察到钆（钪）存在下的共发光现象，研究了该反应的荧光特点和影响因素，确定了反应和测定的最佳条件。钆和钪的引入使原有的铽－均苯四甲酸体系的荧光分别增加了２４０和９５倍。在最佳条件下，对应于钆和钪，铽的浓度分别在５．０×１０－８～３．０×１０－５ｍｏｌ／Ｌ和７．０×１０－８～１．０×１０－５ｍｏｌ／Ｌ的范围内与荧光强度成线性关系，检测限分别为２．０×１０－１０和５．０×１０－１０ｍｏｌ／Ｌ采用多点增量标准加入法测定了合成样品和包头稀土样品中的铽。回收试验的回收率为１００．１±０．０１％和９９．１±０．０３％。     

Synthesis,mechanical properties of fluorescent carbon dots loaded nanocomposites chitosan film for wound healing and drug delivery

Fluorescent carbon nanoparticles (CNPs) are a new class of carbon nanomaterials and have demonstrated excellent optical properties, good biocompatibility, great aqueous solubility, low cost, simple synthesis, etc. Since their discovery, various synthesis methods using different precursors have been developed, and are mainly classified as top-down and bottom-up approaches. The contact angle measurements revealed that wettability of plain chitosan film reduced due to addition of carbon nanoparticles. It was found that, impregnation of carbon dots into chitosan film resulted in an almost seven fold decrease in the water absorption capacity of the film. The equilibrium moisture uptake (EMU) data of plain chitosan and CQD-loaded chitosan films were interpreted by GAB isotherm and related parameters were also evaluated. Finally, the moisture permeation capacities of the plain Ch and Carbon dots loaded sample Ch/CNP was found to be 1758 and 956 g/m²/day. In addition, Bovine serum albumin (BSA) adsorption was found 24.2 mg/m² for plain sample while it decreased to 14.1 mg/m² as CDs were incorporated into film matrix. The anti-oxidant property was evaluated in terms of % scavenging of DPPH, SO and Hydroxyl radicals. It was observed that for all the free radicals, % scavenging increased with increase in CDs contents in the films.