环氧树脂基双组分水性聚氨酯的制备及其在木器涂料中的应用

为提高双组分水性聚氨酯的室温交联速度，将 N-苄基乙醇胺引入到环氧树脂制备了环氧树脂基水性多元醇，表征了多元醇的化学结构，并测定了其相对分子质量、粒径分布和玻璃化温度等主要技术参数。将环氧树脂基水性多元醇与多异氰酸酯配合制备了双组分水性聚氨酯，采用红外光谱法研究了室温交联反应过程。研究结果表明：多元醇分子结构中引入苄胺基加快了双组分水性聚氨酯的交联反应速度。将双组分水性聚氨酯制备成水性木器涂料，漆膜具有优异的耐冲击性、附着力、柔韧性、光泽、耐液体介质、硬度、丰满度等性能。     

Effect of structure on the properties of polyurethanes based on aromatic cardanol-based polyols prepared by thiol-ene coupling

Industrial-grade cardanol and 2-mercaptoethanol were reacted to generate hydroxyl-functionalized cardanol by UV, free-radical-initiated thiol-ene coupling between the double bond moieties of the cardanol long carbon side chain and thiol functional groups. The average hydroxyl number of the hydroxyl-functionalized cardanol was controlled by reaction time, with the hydroxyl values of this ranging within 168–201 mg KOH g⁻¹. This cardanol was then used as a polyol to prepare cardanol-based polyurethane with hexamethylene diisocyanate and a NCO/OH ratio of 1. To compare the effect of cardanol-based polyols with the properties of cardanol-based polyurethane, cardanol modified with 10-undecylenate was used as a raw material to prepare cardanol-based polyols, including the long carbon chain of 10-undecylenate. All properties were examined, and data revealed that cardanol-based polyols including this long carbon chain can improve the hydrophobic and mechanic properties of the cardanol-based polyurethane.     

酚醛树脂胶粘剂研究进展

酚醛树脂胶粘剂具有优良的耐水性、耐热性、耐候性,粘接强度高及化学稳定性好等优点而被用于诸多领域。但是其还存在固化温度高、热压时间长、易透胶、有甲醛释放、原料成本高且不可再生等缺点。综述了快速固化和低游离甲醛含量酚醛胶粘剂,三聚氰胺、尿素、木质素、生物质焦油以及其他改性酚醛树脂胶粘剂,并对其存在问题和发展前景作了分析和展望。     

The effect of dense polymer brush on the microfibrillated cellulose for the mechanical properties of poly(ε-caprolactone) biocomposites

Two different cellulosic fibers [pristine microfibrillated celluloses (MFCs) and 2,2-bis(hydroxymethyl)propionic acid-modified MFCs (bis-MPA-modified MFCs)] were grafted by poly(ε-caprolactone) (PCL) molecules through the ring-opening polymerization (ROP) method. The PCL-grafted MFCs were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and elemental analysis. The results showed that the grafting of PCL on the bis-MPA-modified MFCs was more efficient than that of the pristine MFCs due to the higher density of the activated hydroxyl groups on the bis-MPA-modified MFCs. Furthermore, the numerous PCL chains bound to the bis-MPA-modified MFCs (PCL-g-mMFC) demonstrated the stronger interfacial adhesion between the modified MFC fibers and the PCL matrix, as well as the greatly improved dispersion of the modified MFCs in the PCL matrix of the PCL/cellulose biocomposites.     

生物质加压液化制备生物油研究进展

回顾了生物质加压液化技术的发展历程,对生物质加压液化的反应机理进行了分析,分别探讨了生物质原料、液化溶剂、催化剂、液化气氛、液化温度、压力及反应时间对液化效果的影响。分析了目前液化生物油提质精炼的研究进展,指出在这方面的研究需进一步加深,为以后的工业化生产积累经验。     

用活性炭回收挥发性有机溶剂的研究进展

简要介绍了挥发性有机溶剂的危害、回收意义和常见的回收技术。重点阐述了用活性炭回收挥发性有机溶剂的技术,就最常见的汽油回收炭、丙酮回收炭、丁酮回收炭为例,阐述了活性炭在溶剂回收方面的研究进展。     

Migration of conventional and new plasticizers from PVC films into food simulants: A comparative study

PVC is one of the resins with the higher quantity of additives and the possibility of migration is always a concern when its intended use is food packaging. In this study, the migration of several plasticizers was investigated with the aim of finding out a relationship between migration and conformance with legislation in force, and tensile properties as well. Therefore, six PVC cling films intended to come into contact with foodstuffs have been formulated in order to have same hardness and thickness. The reference film was produced with DEHA and ESBO, while the other films were produced with conventional plasticizers (ATBC and Polyadipate), new plasticizers from renewable resources (Mixture of glycerin acetates – MGA and Acetic acid esters of mono- and diglycerides of fatty acids – AGM) or a plasticizer employed in toy and childcare applications (DEHT). The films were evaluated as to the overall and specific migration to food simulants and the effect of the formulation was studied. The results have shown that the coefficient of apparent partition of DEHT is similar to that of DEHA, whereas MGA and AGM plasticizers displayed higher coefficients of apparent partition than the other plasticizers under study. This difference in migration has been attributed to the different molecular structures of plasticizers. In addition, commercial films have been evaluated as to plasticizers concentration and specific migration into food simulants. It was found that 25% of the samples comply with the specific migration limits for fatty foods contact while 50% might be used for contact with fatty foods with FRF 2–5. On the other hand, all commercial samples showed no restriction for aqueous acidic food contact. Thus, it has been demonstrated that a contact for prolonged time up to 40 °C did not promote the migration of plasticizers into acidic foodstuffs, but the migration of plasticizers to fatty foods can be high (75%–90% loss of plasticizers) and limit the use of PVC films as fatty food packaging.     

Thermal microstress measurements in Al2O3/SiC nanocomposites by Cr3+ fluorescence microscopy

Alumina/SiC ‘nanocomposites’ show significant property improvements compared with pure alumina. The improvements are thought to stem at least in part from the microstresses caused by the thermal expansion mismatch between alumina and SiC. These microstresses have been measured previously by neutron and X-Ray diffraction. This paper reports stress measurements using Cr³⁺ fluorescence microscopy of the alumina matrix. The results show that although fluorescence microscopy is less powerful than the diffraction techniques in terms of the range of information provided, it does provide an alternative method of measuring subsurface microstresses in these materials which is quicker, cheaper and higher in spatial resolution.