改性水性丙烯酸酯胶黏剂的研究进展

目的 综述近年来水性丙烯酸酯胶黏剂改性方法和合成技术的国内外研究进展,以期为水性丙烯酸酯胶黏剂的进一步研究及在包装材料领域的应用提供参考。方法 介绍丙烯酸酯胶黏剂的组成,综述水性丙烯酸酯胶黏剂的主要改性方法,阐述种子乳液聚合、反相乳液聚合、核壳乳液聚合、微乳液聚合、细乳液聚合、无皂乳液聚合、超声辐照乳液聚合、乳液互穿聚合物网络和Pickering乳液聚合等技术合成不同种类和性能丙烯酸酯胶黏剂的相关研究,概述丙烯酸酯胶黏剂在包装、纺织等领域的具体用途。结论 对水性丙烯酸酯胶黏剂的未来趋势和研究前景进行了展望,将多重改性方法有机结合,开发高性能水性丙烯酸酯胶黏剂,合成并应用新型生物基胶黏剂、特种功能性胶黏剂、低成本绿色水性丙烯酸酯胶黏剂。     

秸秆人造板用胶黏剂研究进展

农作物秸秆人造板的使用填补了我国因木质资源短缺造成木基人造板供不应求的缺口,胶黏剂的性能则成为了制约秸秆人造板性能的关键因素。综述了秸秆人造板用脲醛树脂、酚醛树脂、异氰酸酯、三聚氰胺树脂、橡胶等胶黏剂的性能和使用现状,分析了这些胶黏剂在制作秸秆板时存在的突出问题。并且针对这些问题,介绍了无机胶黏剂、生物胶黏剂等新型胶黏剂在秸秆人造板中的应用,最后指出了传统的有机胶黏剂和新型的无机、生物胶黏剂的发展方向,为秸秆人造板用胶黏剂的进一步研究提供参考。     

漫谈我国胶黏剂合成行业

胶黏剂的应用在国民经济的各个领域都有体现，是我国化学工业中发展速度最快的产业之‘。随着合成胶黏剂正在越来越多地代替机械联结，胶黏剂将不断地向更多的领域扩展。本文简单介绍了当前我国胶黏剂发展的一些基本情况，概述了胶黏剂的基本含义，最后根据我国胶黏剂行业中所暴露的弊端，给出了未来胶黏剂发展的趋势，最后进行了分析总结。     

硅酸盐胶黏剂的研究与应用

硅酸盐胶黏剂环保无毒、制备简便、成本低廉、粘接性能好,其应用范围涵盖了国民经济和百姓日常生活的方方面面。近年来,硅酸盐胶黏剂在一些新领域也得到了发展和应用。从研究现状和应用情况两个方面总结和评述硅酸盐胶黏剂的最新研究进展,并对硅酸盐胶黏剂的发展前景作出展望,以期为硅酸盐胶黏剂的深入研究提供必要的参考资料。     

微晶纤维素改性大豆蛋白胶黏剂的黏结性能及热压工艺的研究

应用微晶纤维素和尿素溶液对大豆分离蛋白进行改性,得到了一系列大豆蛋白胶黏剂,考察了微晶纤维素含量、尿素浓度对胶黏剂胶黏强度的影响;进一步优化了胶黏剂的热压条件。实验结果表明:微晶纤维素改性大豆蛋白胶黏剂(MSP)的胶黏强度比未改性大豆蛋白胶黏剂的大,微晶纤维素含量对改性大豆蛋白胶黏剂胶黏强度的影响存在一个最佳值;微晶纤维素和尿素共同改性大豆蛋白胶黏剂相比仅有微晶纤维素改性的大豆蛋白胶黏剂,其胶黏强度进一步提高。研究MSP热压条件发现,其最佳热压条件为:热压温度100℃;热压压力2 MPa;热压时间10 min。     

瓦楞纸板淀粉胶黏剂制胶原理与品质控制

介绍了瓦楞纸板生产线用淀粉胶黏剂的粘合原理与配制机理,讨论淀粉胶黏剂主要质量影响因素,阐述其性能检测方法,并分析淀粉胶黏剂常见质量问题与解决办法。有助于生产和品质人员根据实际情况改善与控制胶黏剂品质,满足纸板生产的实际需要。     

室温固化淀粉胶黏剂的研究进展

淀粉作为一种天然高分子材料,具有储量丰富、价格低廉、可生物降解以及可再生等优点,在胶黏剂领域的应用逐渐受到重视,然而以淀粉为原料制备的胶黏剂存在耐水性差、不易储存、流动性不好、胶接强度不够等缺点,因此要对其进行改性才能满足行业要求。重点论述了提高淀粉胶黏剂耐水性、胶接强度、储存稳定性、流动性的一些改性方法的研究进展,并探讨了室温固化淀粉胶黏剂未来的发展方向。     

木材胶黏剂仿生改性研究进展

目前,利用无醛胶黏剂替代醛类树脂胶黏剂制备人造板产品成为木材胶黏剂研究热点,符合国家可持续发展和“双碳”战略。生物仿生为木材胶黏剂的改性和性能提升提供了设计灵感,是一种新兴且有效的改性策略。通过仿生设计与改性,无醛木材胶黏剂的耐水性、防霉性、涂布预压性等得到显著提升的同时可以赋予胶黏剂功能性,是木材工业研究热点之一。本文综述了无醛木材胶黏剂仿生改性研究进展,按照仿生原理分为生物化学仿生木材胶黏剂(包括灵感来源于贻贝湿态黏附或模拟生物矿化、细胞壁构筑和重组键合网络过程等)以及结构仿生木材胶黏剂(包括灵感来源于壁虎脚趾微纳刷状结构、蜘蛛丝微相分离结构、珍珠层“砖和砂浆”结构、墨鱼骨多孔结构、弹簧螺旋结构等)。重点介绍了仿生原理、配方设计、胶黏剂性能和潜在应用价值,以期为木材胶黏剂的开发与高附加值利用提供参考。     

一种阻水耐磨编织袋胶黏剂的制备方法

本文介绍了一种满足编织袋胶黏性能的同时能延长编织袋使用寿命的胶黏剂的制备方法。添加有天然橡胶乳,天然橡胶最大的特点是胶黏性强,韧性强,环境友好,应用广泛,添加天然胶乳能增加胶黏剂的胶黏性和抗老化性能,延长编织袋的使用寿命,添加的甲基丙烯酸甲酯能增加编织袋的耐磨性能。     

改性大豆蛋白基胶黏剂的研究进展

目的 解决大豆蛋白胶黏剂胶合强度低、粘度大的问题,使制得的胶黏剂能满足室内使用人造板及胶合制品的要求.方法 通过综述改性大豆蛋白胶黏剂在胶合强度、粘度方面的研究进展,分析原子转移自由基聚合(ATRP)法改性大豆蛋白胶黏剂的前景.结论 采用ATRP对大豆蛋白进行接枝改性,可在提高胶合强度的同时保障粘度适中.ATRP改性大豆蛋白胶黏剂为改性大豆蛋白胶黏剂的研究提供了新的探索道路,对制备粘度适中、胶合强度.     

Solubility of core materials in aqueous polymeric solution effect on microencapsulation of curcumin

Curcumin, the main active constituent of turmeric herb (Curcuma longa L.) have been reported to possess many medicinal values. The application of curcumin in dermatological preparations is limited by their intense yellow color property, which stains the fabric and skin. The objectives of this study were to reduce the color staining effect and enhance the stability of curcumin via microencapsulation using gelatin simple coacervation method. As for curcumin, ethanol and acetone were used as coacervating solvents. Curcumin was dispersed in ethanol while dissolved in acetone. Irrespective of the types of coacervating solvents used, microencapsulation resolved the color-staining problem and enhanced the flow properties and photo-stability of curcumin. Nevertheless, it was found that more spherical curcumin microcapsules with higher yield, higher curcumin loading, and higher entrapment efficiency were obtained with acetone than ethanol. The in vitro release of curcumin after microencapsulation was slightly prolonged. Further evaluation of the effects of solubility of core materials in coacervating solvent or polymeric aqueous solution using six different drug compounds, namely, ketoconazole, ketoprofen, magnesium stearate, pseudoephedrine HCl, diclofenac sodium, and paracetamol, suggested that the solubility of core materials in aqueous polymeric solution determined the successful formation of microcapsules. Microcapsules could only be formed if the core materials were not dissolved in the aqueous polymeric solution while the core materials could either be dissolved or dispersed in the coacervating solvent. In summary, microencapsulation not only circumvents the color-staining problem but also improved the stability and flowability of curcumin. The solubility of core material in aqueous polymeric solution plays a pivotal role in determining the successful formation of microcapsules.     

Solubility of Core Materials in Aqueous Polymeric Solution Effect on Microencapsulation of Curcumin

Curcumin, the main active constituent of turmeric herb (Curcuma longa L.) have been reported to possess many medicinal values. The application of curcumin in dermatological preparations is limited by their intense yellow color property, which stains the fabric and skin. The objectives of this study were to reduce the color staining effect and enhance the stability of curcumin via microencapsulation using gelatin simple coacervation method. As for curcumin, ethanol and acetone were used as coacervating solvents. Curcumin was dispersed in ethanol while dissolved in acetone. Irrespective of the types of coacervating solvents used, microencapsulation resolved the color-staining problem and enhanced the flow properties and photo-stability of curcumin. Nevertheless, it was found that more spherical curcumin microcapsules with higher yield, higher curcumin loading, and higher entrapment efficiency were obtained with acetone than ethanol. The in vitro release of curcumin after microencapsulation was slightly prolonged. Further evaluation of the effects of solubility of core materials in coacervating solvent or polymeric aqueous solution using six different drug compounds, namely, ketoconazole, ketoprofen, magnesium stearate, pseudoephedrine HCl, diclofenac sodium, and paracetamol, suggested that the solubility of core materials in aqueous polymeric solution determined the successful formation of microcapsules. Microcapsules could only be formed if the core materials were not dissolved in the aqueous polymeric solution while the core materials could either be dissolved or dispersed in the coacervating solvent. In summary, microencapsulation not only circumvents the color-staining problem but also improved the stability and flowability of curcumin. The solubility of core material in aqueous polymeric solution plays a pivotal role in determining the successful formation of microcapsules.     

广藿香油微胶囊的制备与性能

以广藿香油为芯材,壳聚糖(CTS)、壳聚糖季铵盐(HACC)、阿拉伯胶(GA)为壁材,采用复凝聚法制备了广藿香油微胶囊。采用扫描电子显微镜(SEM)、激光粒度仪、傅立叶红外光谱(FT-IR)对微胶囊进行表征,并对其热稳定性、缓释性、抗菌性进行了研究。结果表明,微胶囊球形规则、分散性好,湿囊的平均粒径为10.8μm,微胶囊化提高了广藿香油的热稳定性。在相对湿度24%,37℃密封环境中储藏20 d,微胶囊对金黄色葡萄球菌、大肠杆菌的最小杀菌浓度分别为1.25 mg/mL和2.5 mg/mL。     

Preparation of isocyanate microcapsules as functional crosslinking agent by minimalist interfacial polymerization

Isocyanate is an extremely high activity compound that has been extensively used in the chemical materials. In this study, we employ microcapsules in preserving the activity of isocyanates and controlling their release in wood adhesives for plywood. Isocyanate microcapsules were synthesized by a one-step interfacial polymerization in an oil-in-water (O/W) emulsion. The particle size distribution, chemical structure, morphology, activity and stability of the obtained isocyanate microcapsules were characterized by laser particle size analyzer, n-dibutylamine titration, FTIR, SEM, and a universal strength testing machine. The as-synthesized microcapsules had approximately 25% active –NCO group and the core accounted for 77% of the total weight. The isocyanate microcapsules demonstrated satisfactory stability by preserving majority of the active –NCO group and core weight during 180 days of storage. These isocyanate microcapsules were used as functional crosslinking agent for making plywood. The resultant plywood showed higher tensile shear strength than the strength mandated in the Chinese National Standard (GB/T 9846-2015). Furthermore, the wet strength was greatly improved to meet the Class I and II plywood standards. Additionally, the stability of isocyanate microcapsules in wood adhesives were significantly enhanced for a prolonged application time. Their excellent bonding properties and stability make isocyanate microcapsules an ideal additive for use in chemical and manufacturing materials.     

微胶囊技术新进展

微胶囊在医药、农药、食品、化妆品、建筑、生物工程等领域具有广阔的应用前景。随着微胶囊研究的深入和应用领域的延伸,新的微胶囊技术也不断地被创造和开发。文中分别介绍了多流体复合电喷技术、超临界流体快速膨胀技术、自组装技术、多种微胶囊方法复合技术等四项制备微胶囊的新技术,并指出了微胶囊技术正向着包覆率高、功能多样、结构与性能可方便调控、制备成本低的方向发展。     

Micromeritic Properties of Nitrofurantoin Microcapsules

Abstract

In our previous study, we have prepared nitrofurantoin microcapsules using carboxymethylcellulose (CMC) and aluminium sulphate by a coacervation technique. In the present study, the micromeritics of these microcapsules were investigated in terms of standardization of the crude materials employed, the microcapsules product and the dosage forms prepared from these microcapsules. The microcapsules were prepared with a 1:1 core: wall ratio and sieved into three particle sizes. Both the micromeritic properties of the pure drug and the polymer were studied by determining their bulk volume and weight, tapping volume and weight, fluidity, angle of repose, weight deviation, particle size distribution, density and porosity, The particle size range went from approximately 250μm to 3000μm with a peak between 900μm and 1350μm. The results indicate that the flowability and the particle size of the resultant microcapsules were much increased compared with the raw materials. As the microcapsule size increases the porosity also increases but the density decreases.

The weight deviation of the microcapsules first sieved then filled into hard gelatin capsules was carried on according to the USP XXII. Hard gelatin capsule size was found by Lindenwald-Tawashi nomogram as number 3. The geometric mean diameters and the geometric standard deviation of microcapsules were calculated as 750 pm for number distribution and 1275μm for weight distribution and 1.52 for number and weight distribution respectively.

In addition to evaluate whether some kind of glidant will be needed during tableting of microcapsules and filling of them into hard gelatines, “Hausner ratio and consolidation indexes” were calculated.

The results obtained suggest that sustained release dosage forms of nitrofirantoin can be prepared from the obtained microcapsules as far as the micromeritic properties is concerned and the microencapsulation changed the micromeritic properties of the crude materials significantly.     

Micromeritic Properties of Nitrofurantoin Microcapsules

In our previous study, we have prepared nitrofurantoin microcapsules using carboxymethylcellulose (CMC) and aluminium sulphate by a coacervation technique. In the present study, the micromeritics of these microcapsules were investigated in terms of standardization of the crude materials employed, the microcapsules product and the dosage forms prepared from these microcapsules. The microcapsules were prepared with a 1:1 core: wall ratio and sieved into three particle sizes. Both the micromeritic properties of the pure drug and the polymer were studied by determining their bulk volume and weight, tapping volume and weight, fluidity, angle of repose, weight deviation, particle size distribution, density and porosity, The particle size range went from approximately 250μm to 3000μm with a peak between 900μm and 1350μm. The results indicate that the flowability and the particle size of the resultant microcapsules were much increased compared with the raw materials. As the microcapsule size increases the porosity also increases but the density decreases.

The weight deviation of the microcapsules first sieved then filled into hard gelatin capsules was carried on according to the USP XXII. Hard gelatin capsule size was found by Lindenwald-Tawashi nomogram as number 3. The geometric mean diameters and the geometric standard deviation of microcapsules were calculated as 750 pm for number distribution and 1275μm for weight distribution and 1.52 for number and weight distribution respectively.

In addition to evaluate whether some kind of glidant will be needed during tableting of microcapsules and filling of them into hard gelatines, “Hausner ratio and consolidation indexes” were calculated.

The results obtained suggest that sustained release dosage forms of nitrofirantoin can be prepared from the obtained microcapsules as far as the micromeritic properties is concerned and the microencapsulation changed the micromeritic properties of the crude materials significantly.     

Microencapsulation I. Phase Separation or Coacervation

Phase separation or coacervation is one of the oldest and perhaps the most widely used method of microencapsulation. This paper discusses phase separation or coacervation as a technique of preparing microcapsules. The basic differences between simple and complex coacervation are described and the various factors which influence simple and complex coacervation are discussed. Schematic ternary phase diagrams involved in the phase separation or coacervation processes are included and the basic schemes describing the process of microencapsulation are outlined.     

Fabrication and performances of microencapsulated paraffin composites with polymethylmethacrylate shell based on ultraviolet irradiation-initiated

In order to identify the validity of fabricating microencapsulated phase change material by ultraviolet irradiation-initiated method, the paraffin wax/polymethyl methacrylate microcapsules were prepared. The structural characteristics and thermal properties of the microcapsules were also determined by various techniques. The results of differential scanning calorimetry analyses indicate that the melting and freezing temperatures and latent heats of the microcapsules are 55.8 °C, 50.1 °C and 106.9 J g⁻¹, 112.3 J g⁻¹, respectively. Morphology and chemical characteristic analysis indicate that the spherical microcapsules were formed with average diameter of 0.21 μm and maximum microencapsulation ratio of 66 wt.% without leakage of core materials. The results of accelerated thermal cyclic test show that the microcapsules have good thermal reliability and chemical stability although they were subjected 3000 melting/freezing cycles. Based on all these results, it can be concluded that the microencapsulated paraffin composites have good potential for thermal energy storage purposes and ultraviolet irradiation-initiated method is a prominent candidate for preparing microencapsulated PCMs.