雷奕
,
黑祖昆
,
Mohique
,
Calvo-Dahlborg
,
Jean-Marie
,
Dubois
,
DONG
,
Chuang
金属学报
分析了块状非晶与稳定准晶结构上的异同点, 选择两种稳定准晶(二十面体准晶和十次准晶)相互混乱合, 在保持准晶二十面体基本结构单元的基础上, 增加元素组成的混乱度, 再添加有利于形成高配位多面体的元素Zr, 用急冷方法制备出非晶合金. 对此非晶合金的热力学测试表明, 该非晶形成能力和稳定性与Inoue的Zr65Al7.5Cu17.5Ni10非晶相近.
关键词:
锆基非晶合金
,
null
,
null
Physica Status Solidi a-Applied Research
Ultra-high molecular weight polyethylene (UHMWPE) samples are annealed at 100-degrees-C and the positron annihilation technique is used to study the variances of crystallinity, mean free-volume hole size, and free volume fraction. At the initial annealing stage, the crystallinity of UHMWPE increases. Then the increasing rate slows down along with the annealing time and the maximum crystallinity is reached after about 7 min. The mean free-volume size and free-volume fraction also increase at first, but decrease after reaching their maximum values. Annealing of UHMWPE using a high heating rate is a complicated process in which the thickening of lamellae, recrystallization, changing of void concentration in the crystalline region and free-volume formation, diffusion and relaxation can occur at the same time. The increase of crystallinity can be explained as the thickening of lamellae and perfecting of crystal. The change of lamellae could be described through Wunderlich's equation a2-dl/dt = -k dG(s)/dl. The relation between the O-Ps intensity I3 and free-volume fraction is eluciated by the model put forward by Jean et al. The experimental results are in good agreement with the theories.
关键词:
dependence;polymers
王基伟
,
王建华
,
曹海燕
,
张宝砚
高分子材料科学与工程
合成了一种新型胆甾液晶单体(M1)和一种向列液晶单体(M2),通过与聚硅氧烷(PMHS)接枝共聚得到了系列侧链液晶聚合物P1～P6,通过傅立叶变换红外光谱(FT-IR)、差示扫描量热仪(DSC)、热失重分析(TGA)、偏光显微镜(POM)等手段对聚合物的结构、液晶性能及热性能进行了表征.随着胆甾液晶基元的减少,其玻璃化转变温度(Ta)、清亮点(Ti)逐渐降低.聚合物P1～P6均为胆甾型热致液晶,聚合物呈现出典型的胆甾液晶彩色Grand-jean织构、油丝及焦锥织构,并且颜色随温度升高发生变化.
关键词:
胆甾相
,
液晶聚合物
,
织构
,
侧链聚合物
支俊格
,
张宝砚
,
刘作军
,
臧宝岭
高分子材料科学与工程
介晶单体十一烯酸胆甾醇酯(M1)和手性单体丙烯酸薄荷醇酯(M2)通过接枝共聚引入聚甲基含氢硅氧烷(PMHS)中,制得系列侧链聚合物P1～P8.通过DSC、偏光显微镜(POM)、X射线衍射分析(WAXD,SAXS)、旋光仪等手段对聚合物进行了表征.聚合物P1～P8都具有光学活性,均为胆甾型热致液晶,具有较宽的介晶相范围,呈现出清晰的彩色Grand-jean织构及油丝织构.但当M2含量大于30%时,聚合物的液晶性能逐渐变弱.
关键词:
聚硅氧烷
,
手性单体
,
胆甾相液晶
,
Grand-jean织构
,
油丝织构
