Novel Tertiary Amino Containing Blinding Composite Membranes via Raft Polymerization and Their Preliminary CO2 Permeation Performance

Facile synthesis of poly (N,N-dimethylaminoethyl methacrylate) (PDMAEMA) star polymers on the basis of the prepolymer chains, PDMAEMA as the macro chain transfer agent and divinyl benzene (DVB) as the cross-linking reagent by reversible addition-fragmentation chain transfer (RAFT) polymerization was described. The RAFT polymerizations of DMAEMA at 70 °C using four RAFT agents with different R and Z group were investigated. The RAFT agents used in these polymerizations were dibenzyl trithiocarbonate (DBTTC), s-1-dodecyl-s''-(α,α''-dimethyl-α-acetic acid) trithiocarbonate (MTTCD), s,s''-bis (2-hydroxyethyl-2''-dimethylacrylate) trithiocarbonate (BDATC) and s-(2-cyanoprop-2-yl)-s-dodecyltrithiocarbonate (CPTCD). The results indicated that the structure of the end-group of RAFT agents had significant effects on the ability to control polymerization. Compared with the above-mentioned RAFT agents, CPTCD provides better control over the molecular weight and molecular weight distribution. The polydispersity index (PDI) was determined to be within the scope of 1.26 to 1.36. The yields, molecular weight, and distribution of the star polymers can be tuned by changing the molar ratio of DVB/PDMAEMA-CPTCD. The chemical composition and structure of the linear and star polymers were characterized by GPC, FTIR, ¹H NMR, XRD analysis. For the pure Chitosan membrane, a great improvement was observed for both CO₂ permeation rate and ideal selectivity of the blending composite membrane upon increasing the content of SPDMAEMA-8. At a feed gas pressure of 37.5 cmHg and 30 °C, the blinding composite membrane (Cs: SPDMAEMA-8 = 4:4) has a CO₂ permeation rate of 8.54 × 10⁻⁴ cm³ (STP) cm⁻²∙s⁻¹∙cm∙Hg⁻¹ and a N₂ permeation rate of 6.76 × 10⁻⁵ cm³ (STP) cm⁻²∙s⁻¹∙cm∙Hg⁻¹, and an ideal CO₂/N₂ selectivity of 35.2.     

Ce添加对AP65镁合金显微组织及电化学性能的影响

采用熔炼铸造法制备添加不同含量Ce的AP65镁合金。采用X射线衍射(XRD)、扫描电镜(SEM)和电子探针(EPMA)研究Ce对AP65镁合金显微组织的影响。采用恒电流放电、动电位极化扫描、化学浸泡研究不同Ce含量AP65镁合金的腐蚀电化学行为。结果表明:随Ce含量增加,合金中依次出现棒状或簇状的Al4Ce相和块状的Al2Ce相。Ce的添加导致AP65镁合金的电化学性能明显提高,添加0.6%(质量分数)的Ce使AP65镁合金的平均放电电位从-1.648 V(vs SCE)负移到-1.756 V(vs SCE);添加4%的Ce使AP65镁合金具有较小的腐蚀电流密度(19.66μA/cm2)和较高的阳极利用率(84.3%),与未添加Ce的AP65镁合金相比,阳极利用率提高16.6%。     

Effects of storage on quality of carrot juices produced with lactofermentation and acidification

In this study, effects on the yield and the quality of product properties of carrot juice produced with lactofermentation and added citric acid, and with and without total enzymatic liquefaction (Pectinex Ultra SP-L) were investigated. Samples were stored at room temperature for 6 months and analytical changes which might occur were determined at day 0 and after 2, 4 and 6 months by quality control tests. In enzyme-treated samples, the yield and the quality of mineral incrementation were determined. Accordingly, ash and water-soluble dry matter contents were increased in the samples. Galacturonic acid formed after enzymatic breakdown of pectin in the raw material increased the total acidity of the samples. Sensorial tests of the product were also carried out. According to the test results, the products produced with enzyme treatment at day 0, after 2 and 4 months storages were found to be the ones mostly preferred. However the samples without enzyme treatment were preferred by the panelists after long-term (6 months) storage.     

第28届IULTCS国际会议概况及皮革中禁用偶氮染料检测方法的最新进展

简要介绍第28届IULTCS会议概况以及欧盟在皮革中禁用偶氮染料检测方法方面的最新进展。     

红发夫酵母两步碳源流加培养

红发夫酵母是虾青素生产中最具潜力的生物来源。研究中应用PhaffiarhodozymaAs 2 15 5 7菌种 ,通过实验和分析方法确定碳源的两步流加培养方式 ,即第 1步用蔗糖和甘油的混合物 ;第 2步则流加蔗糖和乙醇的混合物。培养结果良好。     

电热解—塞曼原子吸收光谱法用于 总膳食样品中痕量汞的快速测定

目的 进一步推进测汞仪在低含量样品总汞含量检测中的运用。方法 同时采用原子荧光光谱法和测汞仪标准加入法定量检测部分总膳食样品。结果 运用原子荧光光谱法对低汞含量总膳食样品进行检测,样品总汞含量范围为1.33μg/kg～41.14μg/kg;运用测汞仪标准加入法对低汞含量总膳食样品进行检测,样品总汞含量范围为1.32μg/kg～32.07μg/kg。测汞仪标准加入法与原子荧光光谱法对同种总膳食样品中总汞含量检测结果接近。结论 测汞仪标准加入法不仅具有省时、快速检测的优势,而且可以保证测定结果的准确性。     

烧结钕铁硼添加合金元素的研究进展

磁性能优越的烧结钕铁硼永磁材料已成为永磁产业的支柱.过去的二十多年里钕铁硼已经在硬盘驱动器的VCM、电动机、信号发生器、手机和MRI等多种器件中得到广泛应用.在未来,由于汽车和电子应用领域对节能电动机的需求,使得电动机市场有望进一步扩展.因此,研究团队致力于钕铁硼磁性能的提高,从而推进电动机市场的快速发展.本文对近些年...     

加成型导电液体硅橡胶的研究

以α,ω-二乙烯基聚二甲基硅氧烷为基胶,配合气相法白炭黑、导电炭黑、含氢硅油、铂催化剂等,制成加成型导电液体硅橡胶.研究了导电炭黑、气相法白炭黑对加成型导电液体硅橡胶性能的影响.结果表明,随着炭黑用量的增加,导电胶片的体积电阻率下降,当添加量达到25份时形成拐点,当添加量达到35份以后,体积电阻率变化不明显,基本维持在...