PPES／MC尼龙6原位复合材料的制备与表征

利用己内酰胺(CL)单体,采用阴离子原位聚合方法制得了聚芳醚砜(PPES)/MC尼龙6复合材料.FTIR分析结果表明.PPES与己内酰胺之间存在一定的氢键相互作用,使得PPES在己内酰胺熔体中能够很好地溶解.SEM结果表明PPES在MC尼龙6基体中能够较好地分散.差示扫描量热法和X射线衍射法分析结果表明复合材料中PPES对MC尼龙6的结晶起异相成核作用,提高了MC尼龙6的结晶温度,但不改变MC尼龙6的α晶型结构.TG结果表明PPES的加入提高了复合材料的热稳定性能.     

聚酯型聚氨酯/MC尼龙6原位复合材料非等温结晶和熔融行为研究

本文通过己内酰胺阴离子开环聚合法制备了聚酯型聚氨酯(PES-TPU)/MC尼龙6原位复合材料。利用差示扫描量热法研究了PES-TPU/MC尼龙6原位复合材料的非等温结晶行为和熔融行为。结果表明,在聚酯型聚氨酯/MC尼龙6原位复合材料中,聚酯型聚氨酯对基体MC尼龙6的结晶有一定的抑制作用,降低了其结晶速率和结晶温度;复合材料非等温结晶的熔融行为呈现二重熔融峰,其高温熔融峰温随降温速率的提高变化不大,而低温熔融峰温则随降温速率的提高向低温方向移动且峰强度逐渐增强。     

尼龙6/尼龙共聚物共混体系的热行为研究

探讨了两种尼龙共聚物对尼龙６共混改性物的热行为的影响，表明：含酰胺和酯两种基团的共聚尼龙，因其含酯基而减弱了尼龙６分子链间相互作用的结果，促进了尼龙６的结晶作用，致使冰骤冷试样观察不到冷结晶峰，仅含酰胺基团的共聚尼龙，基本上没改变尼龙６分子间的氢键相互作用，但共聚尼龙的非结晶性和无序的链结构，导致它对尼龙６结晶过程的干扰，表现为熔体结晶峰温降低和冷结晶峰温提高及峰强度（峰高）增大。     

DSC法研究纳米SiO2/MC尼龙6原位复合材料的多重熔融行为

借助差示扫描量热仪(DSC)研究纳米SiO2/MC尼龙6原位复合材料等温结晶后的多重熔融行为.结果表明:复合材料的熔融行为呈现三重熔融峰,分别对应于等温结晶过程形成的小晶片、主要结晶组分及完善性较差的组分再结晶和再组合形成较为完善结晶组分的熔融.在高温下结晶,纳米粒子含量的增加提高了体系再结晶、再组合程度;在低温下结晶,当纳米粒子含量较低时,再结晶、再组合程度相对于纯MC尼龙6有所降低,进一步增加纳米粒子的含量,再结晶、再组合的程度又逐步提高.     

MC尼龙6／ZnO纳米复合材料制备

将铝酸酯偶联剂和纳米ZnO同时用超声分散在熔融的己内酰胺中,一步原位聚合制备MC(单体铸塑)尼龙6/ZnO纳米复合材料,应用正交试验对偶联剂的用量和超声温度、时间等工艺参数进行了优化.结果表明,当超声温度为80℃、超声时间为20 min、偶联剂加入量为1.0%(质量分数)时,合成的MC尼龙6/ZnO纳米复合材料力学性能最优.通过SEM和XRD对MC尼龙6/ZnO纳米复合材料进一步的表征表明,ZnO在基体中达到了纳米级的分散,结晶形态理想.     

MC尼龙6/TiO2原位纳米复合材料等温结晶动力学的研究

采用差示扫描量热法(DSC)研究了阴离子原位聚合法制备的铸型尼龙6(MC尼龙6)/TiO2纳米复合材料的等温结晶行为,并应用Avrami方程分析了MC尼龙6的等温结晶动力学过程.结果表明纳米TiO2对MC尼龙6基体具有异相成核作用,使其原位纳米复合材料结晶速率常数变大,半结晶时间变小.Hoffman成核结晶理论计算结果表明,原位纳米复合材料的Kg(与结晶温度无关而与成核方式有关的参数)大于MC尼龙6且随着纳米含量的增加而增加,说明纳米TiO2阻碍了MC尼龙6分子链的运动,同时尼龙6由晶核生长占主导地位逐渐向成核机制占主导地位转变.     

尼龙66与尼龙6及其共混物的熔融与结晶行为

分别将尼龙66(PA66)、尼龙6(PA6)以及不同比例的PA66/PA6共混物,经双螺杆挤出机挤出造粒,得到不同类型的PA粒料。使用自动黏度测定仪测试了挤出加工前后PA66和PA6的相对黏度,其中PA66和PA6的相对黏度分别下降了10.1%和2.5%。结果表明,PA66与PA6经过双螺杆挤出加工后都产生了降解现象,且在相同的加工条件下,PA66比PA6降解得更快。采用衰减全反射傅里叶变换红外光谱(ATR–FTIR)与差示扫描量热(DSC)法研究了PA66、PA6及其不同比例共混物的熔融与结晶行为。结果表明,加工历史对PA66与PA6的熔融与结晶行为影响很大,当两者共混时,PA6质量分数超过40%时共混物才开始出现PA6的熔融峰与结晶峰。     

纳米二氧化硅／MC尼龙6原位复合材料非等温结晶动力学

通过阴离子开环聚合法制各纳米二氧化硅／MC尼龙6原位复合材料,采用差示扫描量热法研究MC尼龙6及其原位纳米复合材料非等温结品行为,并利用修正Avrami方程的Jeziomy和Liu的方法进一步处理原位纳米复合材料的非等温结晶动力学,结果表明在纳米二氧化硅／MC尼龙6原位复合材料中,纳米二氧化硅对基体MC尼龙6的结晶有一定的成核作用,并提高了其结品速率。     

尼龙1010／马来酸酐接枝聚乙烯共混体系结晶行为和力学性能的研究

将尼龙1010与马来酸酐接枝聚乙烯进行熔融共混,使用DSC、扫描电镜等方法研究了共混物的结晶行为、共混物形态以及力学性能。结果表明:接枝聚乙烯通过与尼龙1010在熔融共混时生成的接枝共聚物改善了共混组份两相之间的相容性和共混形态;共混物中尼龙组份的结晶熔融热焓下降;共混物在保持较高刚性的同时其干态及低温冲击性能较纯尼龙1010有明显提高。     

纳米二氧化硅/MC尼龙6原位复合材料非等温结晶动力学的研究

通过阴离子开环聚合法制备了纳米二氧化硅(SiO2)／MC尼龙6原位复合材料。采用差示扫描量热法研究了MC尼龙6及其原位纳米复合材料的非等温结晶行为；并利用修正Avrami方程的Jeziomy和Liu法进一步处理原位纳米复合材料的非等温结晶动力学。结果表明，在纳米SiO2／MC尼龙6原位复合材料中，纳米SiO2对基体MC尼龙6的结晶有一定的成核作用，并提高了其结晶速率。     

Isothermal and nonisothermal crystallization kinetics of MC nylon and polyazomethine/MC nylon composites

Crystallization kinetics of MC nylon (PA6) and polyazomethine (PAM)/MC nylon (PAM/PA6) both have been isothermally and nonisothermally investigated by different scanning calorimetry (DSC). Two stages of crystallization are observed, including primary crystallization and secondary crystallization. The Avrami equation and Mo's modified method can describe the primary stage of isothermal and nonisothermal crystallization of PA6 and PAM/PA6 composite, respectively. In the isothermal crystallization process, the values of the Avrami exponent are obtained, which range from 1.70 to 3.28, indicating an average contribution of simultaneous occurrence of various types of nucleation and growth of crystallization. The equilibrium melting point of PA6 is enhanced with the addition of a small amount of rigid rod polymer chains (PAM). In the nonisothermal crystallization process, we obtain a convenient method to analyze the nonisothermal crystallization kinetics of PA6 and PAM/PA6 composites by using Mo's method combined with the Avrami and Ozawa equations. In the meanwhile, the activation energies are determined to be ?306.62 and ?414.81 KJ/mol for PA6 and PAM/PA6 (5 wt %) composite in nonisothermal crystallization process from the Kissinger method. Analyzing the crystallization half‐time of isothermal and nonisothermal conditions, the over rate of crystallization is increased significantly in samples with a small content of PAM, which seems to result from the increased nucleation density due to the presence of PAM rigid rod chain polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2844–2855, 2004     

Non-isothermal crystallization kinetics of reactive microgel/nylon 6 blends☆

The non-isothermal crystal ization kinetics of reactive microgel/nylon 6 blends was investigated by differential scanning calorimetry (DSC). The Mo equation was employed to analyze the non-isothermal crystallization data. The crystallization activation energies were also evaluated by the Kissinger method. The results show that the crystallization onset temperature (Tonset) and crystallization peak temperature (Tp) decrease with the increase of the content of reactive microgel, whileΔT (Tonset–Tp), the crystallization half-time (t1/2) and the crystal ization enthalpy (ΔHc) increase. The required cooling rates of blends are higher than that of neat nylon 6 in order to achieve the same relative crystallinity in a unit of time. The crystallization activation energies of the reactive microgel/nylon 6 blends are greater than those of the neat nylon 6. When the content of reactive microgel is 30%, the relative crystallinity (Xt) reaches the maximum.     

Toughening and phase separation behavior of nylon 6–PEG block copolymers and in situ nylon 6–PEG blend via in situ anionic polymerization

We have prepared in situ molded products of morphologically different nylon 6/polyethylene glycol (PEG) copolymers and their blends via anionic polymerization of ε-caprolactam in the presence of several kinds of PEG derivatives using sodium caprolactamate as a catalyst and carbamoyl caprolactam derivative as an initiator. Three carbamoyl caprolactams, such as tolylene dicarbamoyl dicaprolactam (TDC), hexamethylene dicarbamoyl dicaprolactam (HDC), and cyclohexyl carbamoyl caprolactam (CCC), with different functionalities and activities were used. Phase separation behavior was investigated by dynamic mechanical thermal analysis (DMTA) and DSC during in situ polymerization and melt crystallization. The mechanical properties of these molded products were evaluated. PEG segments in the block copolymers showed amorphous characteristics, whereas a large fraction of unreacted PEG segments was crystallized in as-polymerized samples, except for the products obtained using the CCC activator. The presence of PEG derivatives retarded the crystallization of nylon 6 part during in situ polymerization as well as melt crystallization. However, PEG segments did not alter the crystalline structure of nylon 6, showing α-crystalline modification. The nylon 6–PEG–nylon 6 triblock copolymers showed the highest impact strength, whereas the nylon 6–PEG diblock copolymers and in situ nylon 6–PEG blends showed no improved toughness. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1285–1303, 1999     

Characterization of nylon 6/ABS blends with and without a maleated polybutadiene as compatibilizer

The physical properties of nylon 6/poly(acrylonitrile-butadiene-styrene) terpolymer (ABS) blends using a maleated polybutadiene (denoted PB-g-MA) as compatibilizer were investigated. The morphology results reveal that ABS domain sizes decrease with an increasing compatibilizer content, suggesting the good interaction between the nylon 6 matrix and the ABS dispersed phase. Cooling conditions and compatibilizer contents strongly affect the crystalline structure of nylon 6, as determined from X-ray diffraction and non-isothermal crystallization thermal analyses. The coexistence of α- and predominantly γ-form crystals for the 10 phr compatibilized blends was observed. Isothermal crystallization kinetics suggests that the introduced compatibilizer impeded the growth rate of the crystals, especially for the higher compatibilizer content. The compatibilizer was beneficial in enhancing the thermal stability of the blends.     

Supercritical CO2-assisted synthesis of poly(acrylic acid)/nylon6 and polystyrene/nylon6 blends

Poly(acrylic acid)/nylon6 and polystyrene/nylon6 blends were prepared using supercritical CO₂ as substrate-swelling agent and monomer/initiator carrier. Both supercritical CO₂/nylon6 binary system and SC CO₂/monomer/nylon6 ternary system were studied. Virgin nylon6 and synthesized blends were characterized through differential scanning calorimetry, infrared spectroscopy, and polarizing microscopy. Supercritical CO₂-induced crystallization was found in modified nylon6.     

注塑级PPES/PPS共混合金热性能及结晶性能的研究

通过熔融挤出、注塑成型的方法制备了配比不同的含二氮杂萘酮结构的聚芳醚砜(PPES)和聚苯硫醚(PPS）的共混物，对材料的热性能及结晶性能进行了研究。热失重研究表明，在所组成范围内PPS的加入并未降低共混物的热性能，但使共混物的热变形温度有所降低；PPES的加入使PPS的结晶受到阻碍，当PPES质量分数达80％时，PPS产生了晶格缺陷，从而不能形成完善的球晶，退火过程有利于提高共混物的热变形温度，使PPS形成更完善的球晶。     

MCPA6/纳米TiO2原位复合材料的熔融行为

采用差示扫描量热法(DSC)研究了铸型尼龙6(MCPA6)及其纳米TiO2原位复合材料的等温结晶与非等温结晶晶体的熔融行为。结果表明：MCPA6／纳米TiO2原位复合材料等温结晶晶体的熔融行为呈现三重熔融峰，非等温结晶晶体的熔融行为呈现二重熔融峰；其高温熔融峰温随等温结晶温度或降温速率的变化基本不变，而低温熔融峰温则随等温结晶温度的升高或降温速率的减小而提高；纳米TiO2的加入对MCPA6有一定的成核作用，使其熔点提高。