聚芳硫醚砜/聚苯硫醚合金的流变行为

将聚芳硫醚砜(PASS)和聚苯硫醚(PPS)按照不同的比例通过熔融共混制备高性能合金材料。采用旋转流变仪分析了纯PASS树脂和共混物熔体的流变行为。结果表明,纯PASS树脂通过提高剪切速率和升高温度来改善熔体的流动性效果不佳;在实验范围内,随着合金中PPS含量的增加,合金的加工流动性得到明显改善,当PPS的质量分数为50%时,PASS/PPS合金的熔融加工温度最低,凝胶点降至270℃。     

熔融挤出制备PPS／PES共混物的研究

本文运用示差扫描量热分析(DSC)技术研究了经熔融挤出共混方法制备的PPS/PES共混物的熔融、结晶行为。结果表明,PES对PPS的熔融、结晶行为有深刻影响,混入PES使PPS的熔融行为发生了变化,使PPS的结晶能力提高;PPS和PES有一定的相容性,混入PES使PPS的玻璃化转变温度提高;不同的热历史对PPS/PES共混物的熔融行为有深刻的影响。     

多次DSC扫描对聚苯硫醚/尼龙6共混物中聚苯硫醚组分结晶行为的影响

用DSC研究了多次重复扫描对聚苯硫醚/尼龙 6(PPS/PA6)共混物中PPS组分结晶行为的影响.随扫描次数增加,熔融温度低时,PPS的结晶温度稍有提高;熔融温度高时,PPS的结晶温度逐步降低;而且出现2或3个结晶峰.共混物中PPS组分除结晶温度比纯PPS的高外,随熔融温度和扫描次数增加,仅有单一高温结晶峰 .以上结果可用自成核、异相成核和交联作用来解释.     

PPS／PES共混体系热行为特征的研究

本文借用TBA、DSC技术,研究了聚苯硫醚(PPS)与聚醚矾(PES)共混的相容性,讨论了共混方法对两者相容性的影响,研究了无定形的聚醚矾对半结晶性的聚苯硫醚熔融、结晶和冷结晶行为的影响以及PPS/PES共混物的界面行为。结果表明:溶液共混较机械共混相容性好;且在PES含量为60～70％(重量百分比)时,两组份相容性得到提高并存在较强的界面效应,在DSC谱图上呈现界面相的玻璃化转变;PFS的加入,破坏了PPS原有的结晶聚集态结构,使PPS的熔融双峰变为单峰,并促进了PPS的冷结晶。     

聚苯硫醚/尼龙6共混物的结晶与熔融行为EI北大核心

用 DSC研究了不同组成比的聚苯硫醚 ( PPS) /尼龙 6( PA6)共混物中 PPS和 PA6组分的结晶与熔融行为及其相互作用的影响 ,结果表明 ,PPS在 PA6熔体存在下结晶温度明显提高 ,结晶峰形变窄 ;随 PA6含量增加 ,PPS的结晶温度移向高温 ,甚至 PPS成为分散相 ,这一作用还十分明显 ;而 PPS的熔融温度受共混影响较小 ,结晶了的PPS也使 PA6的结晶温度有所提高 ,但不如 PPS的结晶温度提高明显 ;当 PA6为分散相时 ,PA6的结晶温度才开始降低 ;随 PPS含量增加 ,PA6的起始熔融温度和熔点逐渐降低。     

聚醚醚酮与酚酞型聚芳醚砜共混物的相容性特征

本文借助示差扫描量热(DSC),扭辩分析(TBA)和傅里叶变换红外光谱(FTIR)等技术研究了聚醚醚酮(PEEK)/酚酞型聚芳醚砜(PES-C)共混物的相容性特征。结果表明共混物是部分相容的,共混物的相容程度与共混物的热历史有关。在共混物相容程度较高时,共混物的两个 T_g 随共混物组分的改变彼此向对方移动;共混使对应于 PES-CT_g 的玻璃化转变变宽。PEEK/PES-C 共混物的部分相容性从两者有一定程度的分子链水平的相互作用得到证实。     

热塑性树脂增韧聚苯硫醚的结晶行为

用DSC研究了高性能热塑性树脂聚砜(PSF)、酚酞型聚醚酮(PEK-C)与聚苯硫醚(PPS)共混物的结晶熔融行为,结果表明,PSF、PEK-C主要起阻碍PPS结晶的作用,使Avrami指数n值和冷却结晶函数m值下降;热塑性树脂的T_g越高和熔融温度提高,影响更大。     

聚苯硫醚/聚醚砜共混体系的织构和动态力学行为

本文用偏光显微镜(PLM)和动态扭辫分析(TBA)技术研究了各种组成比聚苯硫醚/聚醚砜(PPS/PES)共混体系的形态结构和动态力学行为。实验结果表明,PPS/PES 共混物是高性能的部分相容的微多相分散体系。PPS/PES共混体系的结构和动态力学行为随组成的变化而变化。      

聚酰胺/聚苯硫醚共混物摩擦学性能研究--(Ⅰ)干摩擦

制备了一系列不同组成的聚酰胺(PA66)和聚苯硫醚(PPS)共混物,对材料的摩擦学性能进行了研究.结果表明,80% φ(PA66)/20% φ(PPS)共混物的摩擦学性能最好.借助扫描电子电镜(SEM)和能量色散谱(EDS)等手段,分析认为,PA66在对偶钢环上形成了不均匀、不连续的牢固转移膜,PPS则不能形成转移膜;共混物中PA66相的存在增强了PPS向对偶面上转移的能力."摩擦热控制模型"适用于PA66/PPS共混物体系,材料的磨损由其在对偶面上形成转移膜的能力及转移膜的性质控制.     

聚酰胺／聚苯硫醚共混物摩擦学性能研究——（I）干摩擦

制备了一系列不同组成的聚酰胺(PA66)和聚苯硫醚(PPS)共混物，对材料的摩擦学性能进行了研究。结果表明，80％φ（PA66)／20％φ（PPS)共混物的摩擦学性能最好。借助扫描电子电镜(SEM)和能量色散谱(EDS)等手段，分析认为，PA66在对偶钢环上形成了不均匀、不连续的牢固转移膜，PPS则不能形成转移膜；共混物中PA66相的存在增强了PPS向对偶面上转移的能力。“摩擦热控制模型”适用于PA66／PPS共混物体系，材料的磨损由其在对偶面上形成转移膜的能力及转移膜的性质控制。     

La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的储氢性能研究

针对两种新型稀土型储氢合金La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2的储氢特性进行研究分析。实验表明,相同温度下,La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的PCT曲线基本重合,且都具有优良的吸氢动力学性能;相比之下,后者的滞后系数要小于前者,吸氢量较大,吸氢速率也较快,故其储氢性能较优。300次吸放氢循环实验结果表明,La0.5Y0.5Ni4.8Al0.2合金的吸氢动力学性能虽然略有下降,但抗粉化性能较好。     

Dy0.6Tb0.3Pr0.1(Fe0.95Mn0.05)x取向晶体的结构与磁致伸缩

采用Ｃｚｏｃｈｒａｌｓｋｉ方法生长了Ｄｙ０．６Ｔｂ０．３Ｐｒ０．１（Ｆｅ０．９５Ｍｎ０．０５）ｘ（１．８５≤ｘ≤１．９５）取向合金。所有合金主相为立方Ｌａｖｅｓ相结构,择优取向不完整择优取向的方向与Ｘ的大小有关。研究了沿着这些样品的生长方向的磁致伸缩性能以及磁致伸缩性能与压力之间的关系。     

Thermal Stability of Amorphous Hydride Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45)

The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre-sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction(XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were preparedby mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas-eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most oftheir hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. Thecrystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphousMg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep-tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on thecrystallization of amorphous alloys was discussed.     

Acousto-optic interaction in alpha-BaB(2)O(4)and Li(2)B(4)O(7) crystals

Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals.     

Zr65Al7.5Ni10Cu15Co2.5合金的玻璃转变温度

根据Ｚｒ６５Ａｌ７。５Ｎｉ１０Ｃｕ１５Ｃｏ２。５合金的纳米晶，晶体，液体和玻璃比热的测量结果，研究了合金的玻璃转变温度与全金的热力学函数，动力学参数以及加热速度的关系。结果表明，非晶态合金玻璃转变所需转变激活能很小，玻璃转变温度实际上是由于加热速度引起的不同状态的玻璃与液体的热力学平衡温度。     

Nanomechanical characterization of one-step combustion-synthesized Al(4)B(2)O(9) and Al(18)B(4)O(33) nanowires

Two kinds of aluminum borate nanowires, Al(4)B(2)O(9) and Al(18)B(4)O(33), were successfully synthesized by a one-step combustion method through control of the Al:B atomic ratio and synthesis temperature. Both nanowires are single crystalline but have distinguishing growth habits. Nanoindentation tests were performed directly on individual nanowires to reveal their mechanical properties. A 70% reduction in elastic modulus was found in Al(18)B(4)O(33) nanowires compared with their bulk counterpart. Al(18)B(4)O(33) nanowires exhibited higher hardness and elastic modulus than Al(4)B(2)O(9) nanowires.     

Natural Passivity of Amorphous Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 Alloys

The natural passive films forrned on Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 amorphous alloys long-term exposed in air have been studied by X-ray photoelectron spectroscopy (XPS) and Auger electron (including Ar+ ion depth profiling) spectroscopy (AES). The following aspects have been investigated: (1) chemical states of the elements in the films. binding energies and the chemical shifts measured by XPSf (2) structure and composition of the films fand (3) thickness of the passive films determined by AES depth profiling and XPS analysis.     

Plasma surface treatments of poly(l-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)

The surfaces of poly(l-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) were modified by oxygen and nitrogen plasma treatments. The physical and chemical surface characteristics were evaluated by contact angle tests, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The plasma treatments caused an increase in both contact angle and roughening, altered the surface morphology, inserted polar groups, and, consequently, enhanced the hydrophilicity for both PLLA and PHBV polymers.     

An SANS Study of Decomposition Kinetics in Amorphous Cu_(12.5)Ni_(10)Zr_(41)Ti_(14)Be_(22.5)

Phase decomposition in amorphous Cu12.5Ni10Zr411Ti14Be22.5 alloy as annealed in the super-cooled liquid range was studied by applying small angle neutron scattering (SANS). As annealed between 600 K and 700 K, the alloy was observed to decompose into two new amorphous phases,with the second phase precipitates embedded in the matrix of the first. Long time annealing of the alloy results in crystallization in addition to evolution of the decomposed microstructure.The kinetic diagram of the decomposition and crystallization for this alloy is given. The second phase precipitates have several nanometers in size and occupy a quite low volume fraction. The decomposition of the supercooled liquid in overall temperature range exhibits the features of spinodal reaction.