Influence of silane‐modified coconut shell powder on thermal and mechanical properties of thermoplastic elastomers

A silane coupling agent (glycidyloxypropyltrimethoxysilane, GPTMS) was used to modify coconut shell powder (CSP), and the influence of the modified coconut shell powder (G‐CSP) on the thermal and mechanical properties of thermoplastic elastomers (TPEs) was investigated. The thermal stabilities of the G‐CSP‐TPEs were studied using TGA; Young's modulus of the G‐CSP‐TPEs was studied by means of the spherical indentation test and the tensile test, and the tensile test was also used to characterize the tensile strength of the G‐CSP‐TPEs. The results revealed that the specific functional groups of GPTMS were efficiently grafted onto the CSP and that G‐CSP enhanced the thermal stability of the TPEs. Under 8% strain, Young's moduli of 0–7.5 wt% G‐CSP‐TPEs obtained by the spherical indentation test and tensile test were almost equal, while the modulus of 10–15 wt% G‐CSP‐TPEs measured by the latter test was greater than that of the former test. The tensile strength of G‐CSP‐TPEs increased up to a threshold limit (10 wt% G‐CSP), followed by a significant decrease. Micro‐images of the fractured surfaces obtained by SEM indicated that the addition of G‐CSP gradually filled the microvoids in the matrix and enhanced the tensile strength of the composite. As the G‐CSP mass percentage exceeded a threshold limit (>10 wt%), the particles started to agglomerate, resulting in weak interfacial adhesion and inferior mechanical properties. Hence, an optimal amount of reinforcing agent G‐CSP should be added to attain desirable thermal and mechanical properties. © 2020 Society of Chemical Industry     

动态硫化共混型热塑弹性体的增容交联技术

通过恰当的增容技术,可以使原先不相容、性能差的动态硫化共混型热塑弹性体获得优异的使用性能。橡胶组份的交联剂在很多场合也充当了体系的增容剂。本文详细列举了不同种类橡塑体系的增容剂种类,介绍了增容和相关增容技术在制备高性能热塑弹性体中的应用,同时列出了交联剂的类型。     

热塑性弹性体发展现状

热塑性弹性体（TPE）是一种极具发展潜力的聚合物材料。本文介绍了TPE的特性、应用，及其研究现状并指明了它的发展趋势。     

聚烯烃热塑性弹性体的生产与应用前景

介绍了动态流化法和反应器合成法聚烯烃热塑性弹性体的技术进展与发展方向，阐述了聚烯烃类热塑性弹性体的应用领域，预测了我国在相关行业对聚烯烃热塑性弹性体的需求，提出了我国聚烯烃热塑性弹性体产业的发展方向。     

Toward superior applications of thermoplastic elastomer blends: double Tg increase and improved ductility

With the aim of curbing air pollution and addressing climate change, the use of low density thermoplastic elastomers (TPEs) in transportation could be a useful way to lighten the vehicle weight. For that, melt blending of high performance rubber and thermoplastics is an attractive way of preparing high performance TPEs. In this work, several TPEs have been prepared by melt blending of hydrogenated acrylonitrile butadiene rubber (HNBR) with polyamide 6 (PA6), adding different amounts of carboxylated HNBR (XHNBR) as compatibilizer: 40/60/0, 40/42/18, 40/30/30 and 40/18/42 (PA6/HNBR/XHNBR). The resulting blends were investigated using melt rheological measurements, morphological observations (scanning electron microscopy and polarized optical microscopy), dynamic mechanical analysis, differential scanning calorimetry analysis and mechanical tests. A biphasic morphology was noted for all TPEs. An increase in XHNBR amount changes the morphology from dispersed to co‐continuous. This evolution is explained by the change in the melt rheological properties of the HNBR/XHNBR rubber phase. Moreover, the introduction of 42% XHNBR resulted in an increase in the glass transition temperature of both rubber and PA6 phases. This double T_g increase phenomenon was attributed to the interfacial interactions between the carboxyl groups in XHNBR and the amine end groups in PA6. Additionally, thermal analysis revealed a reduced crystallinity of PA6 in the blend, which corresponds to enhanced interfacial interactions. The interfacial adhesion and the co‐continuous morphology resulted in an improved ductility. This study reveals the possibility of obtaining TPE blends with tunable thermal and mechanical properties by controlling both interfacial interactions and morphology. © 2019 Society of Chemical Industry     

"动态硫化"PVC/NBR型TPE的耐油性能研究

本文系统地研究了ＰＶＣ／ＮＢＶ型热塑性弹体，并与ＮＢＲ进行了对比。     

Stratum corneum lipid organization as observed by atomic force,confocal and two‐photon excitation fluorescence microscopy

Skin moisturization is largely a function of stratum corneum barrier capacity, which in turn is a function of the physical state and structural organization of the stratum corneum extracellular lipid matrix [ 1 - 4 ]. Three unsolved key questions with respect to this lipid matrix’ structural organization [ 3 - 6 ] are: i) whether the lipid matrix is constituted by a single‐gel phase or by co‐existing solid (crystalline or gel) domains, ii) whether a separate fluid (liquid crystalline) phase is present and iii) whether the local pH has a direct effect on the lipid matrix’ phase behaviour. Using an array of complementary visual‐related biophysical techniques (e.g. atomic force microscopy and confocal/two‐photon excitation fluorescence microscopy), it was recently shown that reconstituted membranes composed of extracted decontaminated human stratum corneum lipids do not form a fluid phase, but exclusively a single‐gel phase that segregates into co‐existing microscopic domains below pH 6 [ 7 ]. It was further shown that the role of cholesterol is related to dispersion of ceramide‐enriched domains. This effect is counteracted by the presence of free fatty acids, which mix with skin ceramides but not with cholesterol [ 8 ].     

硫化体系对动态硫化EPDM/POE热塑性弹性体性能的影响

采用动态硫化的方法在Haake转矩流变仪上制备了三元乙丙橡胶/聚烯烃(EPDM/POE)热塑性弹性体(TPV),并分别对不同硫化体系和硫化剂用量对TPV交联密度和性能的影响进行了研究。结果表明,随硫化剂用量的增加,TPV的交联密度增大,其中硫黄硫化体系的TPV变化最明显;采用硫黄硫化体系和酚醛树脂硫化体系制备的TPV性能优于过氧化物硫化体系,并且DCP和硫黄分别在用量为0.5份,酚醛树脂在1.0份时性能较佳。     

Microlasers from AIE‐Active BODIPY Derivative

Organic microlasers have attracted much attention due to their unique features such as high mechanical flexibility, facile doping of gain materials, high optical quality, simplicity and low‐cost fabrication. However, organic gain materials usually suffer from aggregation‐caused quenching (ACQ), preventing further advances of organic microlasers. Here, a new type of microlaser from aggregation‐induced emission (AIE) material is successfully demonstrated. By introducing a typical noncrystalline AIE material, a high quality microlaser is obtained via a surface tension‐induced self‐assembly approach. Distinct from conventional organic microlasers, the organic luminescent material used here is initially nonluminescent but can shine after aggregation under optical pumping. Further investigations demonstrate that AIE‐based microlasers exhibit advantages to enable much higher doping concentrations, which provides an alternative way to improved lasing performance including dramatically reduced threshold and favorable lasing stability. It is believed that these results could provide a promising way to extend the content of microlasers and open a new avenue to enable applications ranging from chemical sensing to biology.     

融合2D压缩感知的缩略图格式保留加密隐私保护

目的 随着云存储服务的普及,人们越来越习惯在云中存储图像,但存在高开销的数据传输、数据篡改以及可能泄露用户隐私的问题。为此,本文提出一种新型的基于2维压缩感知(2D compressed sensing, 2DCS)与缩略图格式保留加密(thumbnail-preserving encryption, TPE)结合的数据隐私保护方案。方法 利用确定性二进制对角(deterministic binary block diagonal, DBBD)矩阵作为测量矩阵对原始图像进行压缩采样,压缩采样的观测值能够保留图像的结构相似性,提高视觉上的观感体验,并通过误差像素集和显著性像素集生成关键像素集,利用2维离散小波变换将关键像素集嵌入压缩信号,在保证图像恢复质量的同时极大地去除冗余信息。最后通过TPE使合法用户在隐私性与可用性之间取得良好平衡。结果 该方案能够在压缩图像的同时保留图像的形态和重要特征,在压缩图像以降低存储成本的同时保证图像边缘和纹理等重要部分的重建质量。实验结果表明,重建图像的视觉效果与原图非常接近,实测平均信噪比(peak signal to noise ratio, PSN...