紫外一阶导数光度法测定壳聚糖的脱乙酰度

以盐酸为溶剂 ,N 乙酰基 D 葡萄糖胺为标准品 ,用紫外一阶导数光度法直接测定壳聚糖的脱乙酰度。标准曲线在 0 .0 0 2 5 0 .0 4 0 0mg·ml- 1范围内线性关系良好 ,回归方程dA/dλ =2 .349C + 0 .0 0 0 8(r =0 .9996 )。相对标准偏差为 0 .2 0 %～ 0 .76 % ,回收率为 99.8%～ 10 1.4 %。该法消除了共存物、浊度、色度的干扰 ,准确度高 ,重现性好 ,样品不需特殊处理简单易行     

Evaluation of the Deacetylation Degree of Chitosan with Two‐Abrupt‐Change Coulometric Titration

The two‐abrupt‐change coulometric titration was proposed for the analysis of the degree of deacetylation of chitosan. The potential was indicated by an antimony electrode which could sensitively response to the variation of activity of hydrogen ion in the turbid and viscous chitosan solution. Through this new approach, the deficiency of combination pH glass electrode in that medium is successfully overcome. The degree of deacetylation of chitosan was obtained by the difference of electrolysis time between two inflection points in the electrolysis process. The measurement error, which is caused by the residual acid or alkali in the chitosan, could be eliminated. The degree of deacetylation of four chitosan samples were investigated by this new method, which found to be consist with those determined by proton nuclear magnetic resonance (¹H NMR). The standard deviations were found to be lower than 0.60 % and the whole experimental process can be completed within 15 min. With merit of simplicity, convenience, quickness, accuracy, the proposed new method would possess extensive practicability in scientific research and industrial production.     

薄层色谱综合分离程度的定量量度

薄层色谱对多元组分的分离程度,目前常用信息量~[1]来度量.但由于计算信息量时需人为地固定R_f值的分段,且认为同一区段内的R_f值等同,而不考虑每相邻两组分的R_f差值,也忽略了同一R_f区段内不同R_f值的细微差异.同时,由于薄层色谱分离的信息量并非连续函数,它只能取很有限的若干个分立值.因此,导致有时相同的信息量值却对应着相去甚远     

Degradation of recycled high-impact polystyrene. Simulation by reprocessing and thermo-oxidation

A simulation of the degradation of high-impact polystyrene (HIPS), occurring during service life and mechanical recycling, was performed by multiple processing and thermo-oxidative ageing. All samples were characterized by differential scanning calorimetry (DSC), melt mass-flow rate (MFR) measurements, tensile testing and infrared spectroscopy (FTIR). Multiple processing and thermo-oxidative ageing clearly alter the oxidative stability and the elongation at break of the materials. These changes observed at a macroscopic scale have been related to chemical alterations in the structure of HIPS. The polybutadiene phase was demonstrated to be the initiation point of the degradative processes induced by processing, service life and mechanical recycling. Thermo-oxidative degradation affects more severely the degree of degradation of the material, so it may be deduced that the changes occurring during service life of HIPS are the part of the life cycle that mostly affects its further recycling possibilities and performance in second-market applications.     

Synthesising injectable molecular self-curing polymer from monomer derived from lignocellulosic oil palm empty fruit bunch biomass: A review on treating Osteoarthritis

Osteoarthritis (OA) is a chronic and irreversible degenerative joint disease that most commonly affects individuals in their forties and fifties worldwide due to the continuously increasing life expectancy. Although joint replacement is an effective remedy for severe end-stage OA, the functional outcomes could be unsatisfactory, while the implants might have a limited lifespan. Due to the drawbacks and limitations of the joint replacement approach, bone Tissue Engineering (TE) is one of the promising bone tissue regeneration technologies that aid in cartilage repair and regeneration and has attracted the attention of experts. The advanced development of biopolymers, in particular biopolymer derived from Oil Palm Empty Fruit Bunch (OPEFB), has been utilised in the fabrication of scaffolds that serve as a crucial component in bone TE. The abundant supply of OPEFB biomass and the increasing trend of converting waste into wealth for environmental sustainability have also provided the opportunity and interest to fully apply biopolymer-derived materials for bone scaffolding and other applications. Therefore, this paper aimed to provide a review of the biopolymers derived from OPEFB for the treatment of OA and other related applications. A brief overview of the biomass sources in Malaysia was presented, followed by a discussion on the chemical compositions and pre-treatment methods of OPEFB by using organosolv pre-treatment and enzymatic hydrolysis for maximum glucose recovery, monomer derived from cellulose OPEFB and synthesizing self-curing polymer scaffold. Additionally, a detailed review of the polymeric biomaterials in bone TE for the fabrication of scaffolds were included in this review. Most importantly, the paper described the potential use of injectable polymeric biomaterials that provide a significant benefit in orthopaedic applications. Overall, this paper provides a perspective on the potential of OPEFB-derived injectable scaffolds as an alternative OA treatment and future bone TE applications.     

Synthesis and characterization of copolymers of β-cyclodextrin derivatives

Cyclodextrins (CDs) are cyclic oligosaccharides made up of d-glucose units connected by 1,4-glucosidic linkages. β-CD is a cyclical starch derivative containing seven glucopyranose units. β-CD derivatives have characteristic property of larger surface area, robust mechanical strength, high surface to volume ratio, electrical and optical properties for analyte determination, good dispersion, easy removal of the template, surface modification, functionalization and handling capacity. In this work, an attempt is made to prepare succinyl-β-CD-acrylamide (S-β-CD-AA) copolymer and β-CD-malic anhydride (β-CD-MAH) copolymer. For the synthesis of S-β-CD-AA, S-β-CD derivative is prepared and further, acrylamide (AA) along with cross-linker undergoes free radical copolymerization for the formation of gel like product. The degree of succinylation (DS) of β-CD derivative is estimated. S-β-CD-AA copolymer showed potential swelling, and deswelling characteristic. Another copolymer is prepared from β-CD malic anhydride derivative. Further, the derivative is treated with cellulose and ethylene diamine tetra acetate (EDTA) to form β-CD-MAH copolymer. The two derivatives are characterized by several techniques. Thermal stability of these copolymers is estimated with the help of thermogravimetric analysis. The basic characterization of the presence of functional groups is done using UV–visible spectroscopy, and infrared spectroscopy. The elemental analysis helped to estimate C, H, N, S in the synthesized compounds. The surface morphology characterization is done with the help of scanning electron microscopy. X-ray diffraction analysis helped in determination of crystal structure of β-CD-MAH. β-CD derivatives prepared may be potential candidate to prepare inclusion complex, in drug delivery, drug loading and several similar applications.