Fractionated crystallization of dispersed PA6 phase of PP/PP-g-MAH/PA6 blends

Fractionated crystallization behavior of dispersed PA6 phase in PP/PA6 blends compatibilized with PP-g-MAH was investigated by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), polarized light microscopy (PLM), and wide-angle X-ray diffraction (WAXD) in this work. The lack of usual active heterogeneities in the dispersed droplet was the key factor for the fractionated crystallization of PA6. The crystals formed with less efficient nuclei might contain more defects in the crystal structures than those crystallized with the usual active nuclei. The lower the crystallization temperature, the lesser the perfection of the crystals and the lower crystallinity would be. The fractionated crystallization of PP droplets encapsulated by PA6 domains was also observed. The effect of existing PP-g-MAH-g-PA6 copolymer located at the interface on the fractionated crystallization could not be detected in this work.

Morphology, thermal behavior, and mechanical properties of PA6/UHMWPE blends with HDPE-g-MAH as a compatibilizing agent

A functionalized high-density polyethylene (HDPE) with maleic anhydride (MAH) was prepared using a reactive extruding method. This copolymer was used as a compatibilizer of blends of polyamide 6 (PA6) and ultrahigh molecular weight polyethylene (UHMWPE). Morphologies were examined by a scanning electron microscope. It was found that the dimension of UHMWPE and HDPE domains in the PA6 matrix decreased dramatically, compared with that of the uncompatibilized blending system. The size of the UHMWPE domains was reduced from 35 mu m (PA6/UHMWPE, 80/20) to less than 4 mu m (PA6/UHMWPE/HDPE-g-MAH, 80/20/20). The tensile strength and Izod impact strength of PA6/UHMWPE/HDPE-g-MAH (80/20/20) were 1.5 and 1.6 times as high as those of PA6/UHMWPE: (80/20), respectively. This behavior could be attributed to chemical reactions between the anhydride groups of HDPE-g-MAH and the terminal amino groups of PA6 in PA6/UHMWPE/HDPE-g-MAH blends. Thermal analysis was performed to confirm that the above chemical reactions took place during the blending process. (C) 2000 John Wiley & Sons, Inc.

PA6/UHMWPE/HDPE-g-MAH共混物反应增容作用的研究

通过 DSC、SEM、Molau试验和力学性能测试 ,研究了 PA6/ UHMWPE共混过程中 HDPE- g- MAH对体系的增容作用、力学性能及结晶行为的影响。结果表明 ,共混体系为热力学不相容体系 ;在熔融共混过程中 ,PA6和 HDPE- g- MAH发生化学反应 ,生成的接枝共聚物对 PA6/ UHMWPE体系有增容作用 ,分散性和界面形态以及力学性能明显改善 ;共混体系中两相的结晶行为亦发生变化 ,尼龙组分的熔融热焓明显下降

PA6/SBS-g-MAH共混物的形态与力学性能

利用扫描电子显微镜、偏光显微镜对尼龙6/马来酸酐接枝SBS共混物的形态结构进行了研究,对其力学性能、吸水率进行了测试和表征。结果表明,用马来酸酐接枝的SBS与尼龙6有较好的相容性,其室温和低温下的缺口冲击强度比纯尼龙6有大幅度提高,吸水率有所降低。

PE-MAH的合成及其对PE/NBR的增容作用

聚乙烯(PE)、马来酸酐(MAH)和过氧化二异丙苯(DCP)在溶液中反应,其产物经多次纯化和红外光谱分析证明,MAH以化学键连接到PE分子链上,接枝率达0.5MAH/100E,即相当于平均每个PE上接枝有10个MAH。用不同接枝率的聚乙烯接枝马来酸酐共聚物(PE-MAH)作为极性差别较大的PE和丁腈橡胶(NBR)的相容剂,分别研究其接枝率和用量对共混物的拉伸强度和低温冲击强度的影响,结果发现:PE-MAH增加了PE/NBR的相容性。低温脆断面的扫描电子显微镜观察清楚地反映出PE-MAH的增容作用。本文还提出了增容模型。

Els aliments de les Illes Balears : el formatge Mah??n-Menorca. Hist??ria, proc??s d'elaboraci??, nutrici??, activitats

El objetivo es dar a conocer los alimentos de calidad de las Islas Baleares, que las personas los quieran, los defiendan y tambi??n que los den a conocer a los amigos y familiares en cualquier ocasi??n.

Os efeitos de um programa de exercícios domiciliares em pacientes com Paraparesia Espástica Tropical/Mielopatia Associada ao HTLV-1 (PET/MAH)

Introdução e Objetivos: Os efeitos da prática de exercícios sobre a funcionalidade de indivíduos com Paraparesia Espástica Tropical/Mielopatia Associada ao HTLV-1 (PET/MAH) são desconhecidos. O objetivo deste estudo é avaliar os efeitos de um Programa de Exercícios Domiciliares (PED) e a sua taxa de adesão em indivíduos com PET/MAH. Métodos: Vinte e três participantes com o diagnóstico de PET/MAH, marcha preservada e que não praticavam exercícios há pelo menos um mês foram submetidos ao PED de 20 semanas. Os desfechos primários incluíram os escores de força muscular, contração isométrica voluntária máxima (CIVM) e comprimento muscular dos membros inferiores, dor lombar e nos membros inferiores, EDSS, Escala de Incapacidade do IPEC, Índice de Barthel e SF-36. A taxa de adesão e os eventos adversos também foram mensurados e caracterizados. Resultados: No momento da análise os pacientes foram divididos em dois grupos de acordo com o teste Timed Up and Go (TUG) (<20s vs \226520s). O comprimento dos músculos isquiotibiais e plantiflexores, a CIVM dos membros inferiores e o componente \201CAspectos Sociais\201D da SF-36 apresentaram melhora significativa no grupo TUG <20s. Os indivíduos do grupo TUG \226520s melhoraram significativamente o componente \201CCapacidade Funcional\201D da SF-36. A taxa de adesão foi de 90% no total e os eventos adversos, como fadiga, dor muscular e caimbras foram de intensidade leve a moderada Discussão: Foi observada uma boa adesão ao PED, além de melhora significativa da incapacidade e da qualidade de vida dos indivíduos com PET/MAH. É possível que o grupo TUG \226520s apresente um maior componente neurodegenerativo e, portanto, uma menor probabilidade de incremento da funcionalidade. Conclusões: O PED foi eficaz em melhorar algumas incapacidades e a qualidade de vida dos indivíduos com PET/MAH. Tais resultados reforçam a necessidade de estratégias alternativas ao modelo ambulatorial, que ampliem a participação destas pessoas a programas de reabilitação

Paths to Buddhahood : the "sudden" and "gradual" awakening models in Mah ̄y n̄a and Vajray n̄a Buddhism

Examines the graduated paths of Mah ȳn̄a and Vajrayn̄a Buddhism and the instantaneous paths of Ch'an/Zen, rDzogs chen and Mahm̄udr.̄ The main contention between these approaches relates to how the mental defilements are to be purified and how the positive qualities of Buddhahood are to be realised. After comparing and examining the paths it is argued that the polarisation of the "sudden" and "gradual" approaches is the result of the critical philosophies of late Indian and Tibetan Buddhism, rather than a real spiritual dilemma for adherents of either path.

A way to communicate: A new signage system for the Mah Meri Indigenous community

Today, designers use a diverse range of alternative media to have a more efficient form of communication. This research is to investigate the potential of traditionally-inspired contemporary communication design to bridge cultural understandings between and among Malaysians of diverse racial and ethnic backgrounds. Specifically, I propose to design a new signage system in the Mah Meri indigenous community in Malaysia. This is in view that despite the development of the latest media alternatives in use today, the Mah Meri community still lags behind in terms of utilization of these new communication facilities. This project aims to improve social interactions between this community and visitors. The signage system that I propose will help outsiders to navigate in and around the Mah Meri settlements easier and faster because the system provides relevant information in a simple and easy to understand method. Without this signage system visitors will have difficulty in finding the right directions. This work also endeavours, through the notion of creating a new signage system to enrich the cultural identity of the Mah Meri community based on their beliefs in the elements of nature. This, in turn, will create a niche for the community to promote the uniqueness of their culture and identity to outsiders.

Phase morphology, thermomechanical, and crystallization behavior of uncompatibilized and PP-g-MAH compatibilized polypropylene/polystyrene blends

In this article, we discuss the phase morphology, thermal, mechanical, and crystallization properties of uncompatibilized and compatibilized polypropylene/polystyrene (PP/PS) blends. It is observed that the Young's modulus increases, but other mechanical properties such as tensile strength, flexural strength, elongation at break, and impact strength decrease by blending PS to PP. The tensile strength and Young's modulus of PP/PS blends were compared with various theoretical models. The thermal stability, melting, and crystallization temperatures and percentage crystallinity of semicrystalline PP in the blends were marginally decreased by the addition of amorphous PS. The presence of maleic anhydride-grafted polypropylene (compatibilizer) increases the phase stability of 90/10 and 80/20 blends by preventing the coalescence. Hence, finer and more uniform droplets of PS dispersed phases are observed. The compatibilizer induced some improvement in impact strength for the blends with PP matrix phase, however fluctuations in modulus, strength and ductility were observed with respect to the uncompatibilized blend. The thermal stability was not much affected by the addition of the compatibilizer for the PP rich blends but shows some decrease in the thermal stability of the blends, where PS forms the matrix. On the other hand, the % crystallinity was increased by the addition of compatibilizer, irrespective of the blend concentration.

Photoluminescence of barium-calcium titanates obtained by the microwave-assisted hydrothermal method (MAH)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hineh mah-tov u-mah-naʿim : Psalm 133 ; für Männerchor, Harmonium- und Pianoforte-Begleitung

componirt von Ed. Birnbaum

Mah towu

David Rubin