尼龙1010的多重熔化

本文用差示扫描量热法(DSC)研究了尼龙1010的多重熔化行为。研究了部分扫描,部分扫描再退火,加热速率,冷却速率,依次降温退火对熔化曲线的影响。实验结果表明,在DSC扫描过程中试样经历了连续熔化与再结晶的过程。尼龙1010含有强烈地依赖于其热历史的晶体完全程度的分布,从结构再组合观点解释了熔化曲线上双重和多重熔化峰的原因。     

尼龙1010球晶的熔融

本文利用偏光显微镜研究了尼龙1010等温结晶所生成的几类球晶的熔融现象,测得正环状球晶的熔点(T_m)为182℃,正放射球晶T_m=203℃;混合放射球晶T_m=202～205℃;暗负放射球晶T_m=204～210℃;亮负放射球晶T_m=205～210℃。利用Hoffman T_m-T_ε外推法测得其平衡熔点T_m~0=215℃。     

尼龙1010结晶与熔融行为的研究

用DSC研究了降温速率R对尼龙10 10结晶与熔融的影响,以及室温(RT)和液氮(LN)骤冷退火样品的熔融.降温时结晶温度随R增大线性降低;T_g以上可完成结晶时结晶度相同;结晶起始温度>181℃生成的晶体有三个熔融峰,对应于环状和放射状球晶的转化与熔融;在181℃和T_g间结晶,无放射球晶转化峰;T_g下有结晶放热峰样品加热时有冷结晶发生.RT未退火样品三个熔融峰,退火温度T_α≥180℃样品两个峰,结晶度C∝T_a;LN未退火样品单一熔融峰,T_a>160℃双峰,T_a≤160℃三峰,低温峰温与C均∝T.     

MULTIPLE MELTING AND CRYSTALLIZATION BEHAVIOR OF NYLON 1212

The wide-angle X-ray diffraction (WAXD) patterns of isothermally crystallized Nylon 1212 show that γ-form crystals form below 90℃ and the α-form crystals can exist above 140℃. In the temperature range of 90-140℃, the α-form and γ-form crystals coexist. Variable-temperature WAXD exhibits that the nylon 1212 γ-form does not show crystal transition on heating, while α-form isothermally crystallized at 160℃ exhibits Brill transition at a little higher than 180℃ on heating. The multiple melting behaviors of Nylon 1212 isothermally crystallized from melt come from a complex mechanism of different crystal structures, dual lamellar population and melting-recrystallization. In polarized optical microscope (POM) observations, Nylon 1212 isothermally crystallized at 175℃ shows the ringed banded spherulites. However, at temperatures below 160℃ the ringed banded image disappears, and cross-extinct spherulites are formed.     

不同分子量尼龙1010的结晶与熔融

不同分子量尼龙１０１０的结晶与熔融＊朱诚身王经武王友文杨桂萍（郑州大学材料工程系郑州４５００５２）陈玉莫志深（东北师范大学分析测试中心长春１３００２４）（中国科学院长春应用化学研究所长春１３００２２）关键词尼龙１０１０，分子量，结晶，熔融＊１９９４＿...     

尼龙1010在熔融峰温等温结晶生成晶体的热性质和形态结构

用 DSC,TEM,ED 研究了尼龙1010在熔融峰温等温结晶生成晶体的热性质和形态结构。结果表明该晶体在 DSC 扫描的时间尺度范围内是稳定的,能保持原有的熔融特性,不是低熔点晶体转化而成的晶体。对该晶体进行电子衍射,显示对称的清晰的单晶电子衍射斑点,用尼龙1010的晶胞参数标定电子衍射图,证明是单晶的电子衍射图。     

尼龙610的多重熔融行为及其平衡热力学参数

用DSC,WAXD等方法研究了尼龙610的多重熔融行为。在DSC热谱图上,观察到三个熔融峰并按照部分熔融及分级熔融的观点对各峰的来源作了讨论。根据程序升温及等温结晶和比容测定的结果,求得尼龙610的T°_m及ΔH_m的值分别为517.6K及211.7j/g。     

DENSITY, EQUILIBRIUM HEAT OF FUSION AND EQUILIBRIUM MELTING TEMPERATURE OF NYLON 1010

The density, equilibrium heat of fusion and equilibrium melting temperature of Nylon 1010 were determined by means of infrared spectrum, differential scanning calorimetry, wide angle X-ray diffraction and density measurement techniques. According to Starkweatber' s method crystalline density ρ_c and amorphous density ρ_a were estimated to be 1.098 and 1.003 g/cm~3 respectively by extrapolating the straight lines of the IR absorbanee against density to zero intensity. Owing to the less intense in absorbance and less sensitive to the change in crystallinity of the amorphors band the thus obtained ρ_c was too low in value. Thereby the value of the ratio ρ_c /ρ_a is far less than generally accepted mean value for most crystalline polymers. Accordingly, traditional X-ray diffraction method was used through determining thc crystalline dimension(a=4.9, b=5.4, c=27.8, α=49°β=77.0°, γ=63.5°), and a rather correct value of ρ_c or the crystal density 1.13 g/cm~3 was obtained. The equilibrium heat of fusion △H_m~0 was estimated to be 244.0 J/g piotting △H_m 's of specimens with different crystallinity against their corre sponding specific volumes _(sp), and extrapolating to completely crystalline condition (_(sp)~c= 1/ρ_c) As to the equilibrium melting temperature T_m~0, because of the easiness of recrystallization of melt crystallized Nylon 1010 specimen, the well-known Hoffman's T_m-T_c method failed in determining this value and an usually rarely used Kamide double extrapolation method was adopted. The so obtained value of T_m~0 487 seems to be fairly reasonable.     

尼龙1010球晶的转化

本文利用偏光显微镜研究了尼龙1010球晶的转化。发现在降温过程中放射状球晶多转变成相同光性的环状球晶。升温时正环状转化为正放射状球晶;正、混合放射球晶部分转化为负放射状球晶;黄蓝两瓣球晶在一定温度范围内可与负放射球晶相互转变。多种球晶共存时,混合放射球晶可转变成两瓣、不对称四瓣和六瓣形放射球晶;正、混合坏状分别转变成不对称四瓣和六瓣形环状球晶;最后都以环状球晶熔化。     

尼龙1010结构的研究

本工作通过X-光衍射、红外光谱、示差扫描量热、偏光显微镜、粘弹谱及密度观测,考察了尼龙1010样品,分别从玻璃态结晶与从熔融态结晶后的聚集态结构,发现它的结晶结构与尼龙66相似,但从熔融态结晶的晶格有很大畸变,对所涉及的问题进行了讨论,提出了氢键面畸变的模型。     

MULTIPLE MELTING TRANSITIONS IN POLYURETHANE-UREA ELASTOMERS UNDER EXTENSION

Two melting transitions were observed in linear segmented polyurethane-urea elastomers underextension using thermal, mechanical and X-ray diffraction techniques, and the results are compared.These data indicate both strain-induced and temperature-induced crystallization in the stretchedclastomers, which may result from two different types of crystallites with different melting tempera-tures. These have been assigned as type 1 appearing around 60℃, and type 2 around 30℃. Thetype 1 crystallization can be induced by stretching at room temperature to large strain, and is mechani-cally reversible, but the type 2 crystallization is mainly induced by cooling below its crystallizationtemperature. These two crystalline structures are interchangeable under suitable conditions. Atelongations greater than 300%, the low temperature peak observed on fusion thermograms disappearsor combines with the high temperature peak. When the temperature of the sample is over the meltingpoint of the type 1 crystal, irreversible melting occurs and only the type 2 crystal develops on cooling.The results of stress-strain and stress hysteresis experiments at different temperatures indicate therelative importance of strain-induced and temperature-induced crystallization on the mechanicalproperties of these materials.     

尼龙1010在加热扫描中结构重组的研究

用DSC观察了经不同热处理的尼龙1010的热历史和结构重组的再现过程。合理地解释了DSC曲线上吸热和放热峰的性质,提出预熔结晶峰表征再结晶集合的观点。确定了对结晶完善敏感的热处理温度范围。为尼龙1010的加工和应用提供了部分理论依据。     

MELTING CRYSTALLIZATION BEHAVIOR OF NYLON 66

Analysis of isothermal and nonisothermal crystallization kinetics of nylon 66 was carried out using differentialscanning calorimetry (DSC). The commonly used Avrami equation and that modified by Jeziorny were used, respectively, tofit the primary stage of isothermal and nonisothermal crystallizations of nylon 66, In the isothermal crystallization process,mechanisms of spherulitic nucleation and growth were discussed. The lateral and folding surface free energies determinedfrom the Lauritzen-Hoffman treatment are σ= 9.77 erg/cm~2 and σ_e= 155.48 erg/cm~2, respectively; and the work of chainfolding is q = 33.14 kJ/mol. The nonisothermal crystallization kinetics of nylon 66 was analyzed by using the Mo methodcombined with the Avrami and Ozawa equations. The average Avrami exponent n was determined to be 3.45, Theactivation energies (ΔE) were determined to be -485.45 kJ/mol and -331.27 kJ/mol, respectively, for the isothermal andnonisothermal crystallization processes by the Arrhenius and the Kissinger methods.     

尼龙1010的密度与红外光谱

<正> 尼龙1010作为工程塑料在我国有很多应用,为进一步适应工业发展的需要,我们初步研究了一系列熔融淬火的尼龙1010薄膜样品,在不同的条件下退火,考察了它们的红外光谱与密度的变化;找到了红外光谱吸光度与密度有线性关系的谱带1007cm~(-1),进而得到了尼龙1010无定形密度的外推值;对吸光度与密度线性关系较差的940cm~(-1)谱带也进行了讨论。     

尼龙1010对乙基氰乙基纤维素液晶态的影响

在尼龙1010/乙基氰乙基纤维素/二氯乙酸体系中,尼龙1010/二氯乙酸溶液相与乙基氰乙基纤维素/二氯乙酸溶液相不相容,各自形成相区。在乙基氰乙基纤维索含量一定时,增加尼龙1010的量,使液晶相转变温度提高,液晶相的织构也由于乙基氰乙基纤维素/二氯乙酸溶液相的浓度的增大而发生变化。在受到切应力作用后,液晶溶液形成条带织构,条带的方向与应力方向垂直。随着取向的大分子链的松驰解取向,各条带中沿着大分子链取向的方向上出现许多暗带线.把条带分剖成约0.5-1.0μm长的小块。在足够长的时间后,在切应力的方向上形成许多较宽的带。这些带由许多基本相互平行并与宽带形成一角度的小细带组成。上述现象除了与取向大分子链的松弛有关外,可能还与尼龙1010/二氯乙酸溶液相和乙基氰乙基纤维素/二氯乙酸溶液相的相分离有关。     

X-射线衍射法测定尼龙1010结晶度

根据X-射线散射强度理论,使用图解多重峰方法对尼龙1010三个结晶峰及非晶峰的衍射强度进行校正,首次导出了尼龙1010结晶度计算公式,所得结果与密度及量热测定结果具有很好可比性。     

尼龙1010等温结晶球晶形态与生成条件研究

 本文利用偏光显微镜研究了等温结晶时尼龙1010球晶的形态与生成条件,发现在原始样品熔点附近或高于原始熔点以上温度结晶,主要生成暗、亮与带正环的负光性放射状球晶;熔点以下至195℃主要生成正放射状球晶;在较宽的温度范围内可生成混合光性放射状球晶,与少量的六瓣、两瓣、不对称四瓣形三种异常光性球晶;181℃以下主要生成正环状球晶.     

尼龙1010等温结晶球晶形态与生成条件研究

本文利用偏光显微镜研究了等温结晶时尼龙1010球晶的形态与生成条件,发现在原始样品熔点附近或高于原始熔点以上温度结晶,主要生成暗、亮与带正环的负光性放射状球晶;熔点以下至195℃主要生成正放射状球晶;在较宽的温度范围内可生成混合光性放射状球晶,与少量的六瓣、两瓣、不对称四瓣形三种异常光性球晶;181℃以下主要生成正环状球晶.     

尼龙1010异常光性球晶的旋转观察

通过在偏光显微镜下对尼龙１０１０三类异常光性球晶的旋转观察，发现其消光图案和加一级红补色器时的颜色分布，均随观察角度不同而呈周期性变化，表明其结构单元并并非是沿任一半径均等效排列，而可能是半径不等效的．