多相聚合物体系中界面活性剂的应用开发近况

人们早已认识到多相聚合物共混体系中界面的重要性。穿越相界面的物理作用和化学作用影响着不混溶聚合物共混物及聚合物复合材料的整体性能。强的界面作用会产生良好的界面粘结,并有利于共混物中从连续相到分散相的应力传递或复合材料中从基体树脂到填料的应力传递。尽管界面粘结主要影响体系的机械性能,如强度、韧性等,但     

多相聚合物在正交剪切流场中相形态的模拟

借鉴多组分聚合物相分离的动力学方程，对共混过程的外界流场进行简化并推导了动力学方程。应用形态模拟的CDS算法，对推导的动力学方程进行了数值模拟。模拟结果给出了两相聚合物在简化的流场(正交剪切场)的作用下的相形态的演化过程，在一定程度上反映了共混过程的主要形态演化特征，同时指出了提高模拟精度的途径。本文为多相聚合物共混过程的形态模拟提供了一种新方法。     

聚合物体系对注塑制品熔接痕形态结构及性能的影响

根据材料的性质将常见的聚合物材料分为单一聚合物体系、聚合物与助剂共混体系、聚合物共混体系、聚合物混合物与助剂共混体系和相容性聚合物混合物与助剂的共混体系。在不同的材料体系中,研究熔接痕区域材料的形态结构及其对制品性能的影响。研究表明,增加基体的柔顺性和结晶能力,增大分散相的粘度和增容剂的含量,减小助剂的含量和长径比能减小熔接痕区域拉伸相的长度,增加基体在熔体流动方向相互缠结的能力,可提高制品的力学性能。最后,从材料性质方面提出了在工业生产中材料的选择原则。     

纳米无机粒子选择性分布与迁移对聚合物共混物形态与性能的影响

综述了纳米无机粒子在聚合物合金中选择性分布的影响因素及纳米无机粒子在聚合物中分散的重要性,重点从相行为、相形态、力学性能、电学性能、流变行为、结晶和熔融行为以及光学性能等方面总结了近年来纳米无机粒子在聚合物共混物中的选择性分布与迁移对以聚合物共混物为基体的纳米复合材料的形态和性能的影响。特别强调了如何利用热力学和动力学因素调控纳米无机粒子在聚合物合金中的分布。     

共混高聚物—碳黑复合材料的导电规律

共混高聚物基体-碳黑复合材料比单一高聚物-碳黑复合材料有更高的导电性和较小的电导率,对温度的变化率(PTC)值小。这是因为共混基体形成了多相结构,碳黑较多地进入了亲和力较大的高聚物相或相的界面,局部浓度增高,有利于导电网络的形成。     

无机黏土制备剥离型三元乙丙橡胶/黏土纳米复合材料的新方法 (英文)

先采用喷雾干燥工艺制得无机黏土／超细全硫化粉末丁腈橡胶的共混粉末,再用熔体共混工艺制备了三元乙丙橡胶／黏土纳米复合材料,研究了其微观分散形态。结果表明,采用喷雾干燥工艺并利用超细全硫化胶乳的结构特点,可使未经有机改性的无机黏土以剥离型结构纳米分散在三元乙丙橡胶基体中。     

PP/POE/PA6三元共混物相形态的预测及受混炼顺序的影响

引言对聚合物进行共混是改善其性能的重要方法,多元聚合物共混物结合了多种聚合物的优点,具有更多独特的性能,因此对多元尤其是三元共混物的研究越来越多[1-5]。聚合物共混物的相形态对其性能有着决定性的影响[6-9],因而相形态是共混物研究的一个非常重要的方面[9-12]。     

塑料的弹性体增韧及其影响因素

综述了塑料增韧理论的发展,包括微裂纹理论、多重银纹理论、剪切屈服理论、空穴化理论、逾渗理论等,分析了影响塑料韧性的因素,包括聚合物基体、增韧剂和共混加工工艺等。韧性的聚合物基体以剪切屈服断裂为主,而脆性的聚合物基体以银纹化为主。增韧剂对聚合物韧性的影响包括增韧剂的种类、用量、相尺寸、粒子间距等,共混加工工艺即共混顺序也影响聚合物的韧性。正确地理解聚合物的增韧理论和影响因素,有利于合理地设计出高效的聚合物增韧体系。     

聚硅氧烷改性苯丙乳液—I共混改性

聚合物乳液的共混改性可以得到一些独特的性能，改性的效果取决于共混聚合物的相容性及其形态结构，也取决于共混乳液的稳定性。本文研究了聚硅氧烷改性苯丙乳液的稳定性，聚硅氧烷改性橡胶膜的形态结构、两相间相容性，及其对改性橡胶膜力学性能的影响。ＥＳＣＡ和ＳＥＭ结果表明改性橡胶膜中存在明显的相分离，聚硅氧烷在膜的表面富集；通过技枝共聚使苯丙乳液粒子中含有部分聚硅氧烷，或聚硅氧烷乳液粒子中含有部分苯丙共聚物，两     

碳纳米管在熔融共混过程中分散性的影响因素

综述了在熔融共混制备碳纳米管(CNTs)/聚合物复合材料过程中CNTs的分散机理和分散性的影响因素。重点探讨了聚合物基体相对分子质量、螺杆转速、料筒温度、螺杆结构以及添加剂等因素对CNTs在热塑性聚合物基体中分散性的影响,最后对熔融共混分散CNTs方法进行了展望。     

Effect of nanoclay on the morphology and properties of acrylonitrile butadiene styrene toughened polyoxymethylene (POM)/clay nanocomposites

Here, we report the morphology and properties of melt‐blended poly(acrylonitrile‐butadiene‐styrene) (ABS) toughened polyoxymethylene (POM)/clay nanocomposites at different clay loadings (2.5 and 5 phr). The number average domain diameter (D_n) of the ABS droplets in the (75/25 w/w) POM/ABS blend was gradually decreased with increase in clay loading. The X‐ray diffraction (XRD) study and transmission electron microscopic (TEM) analysis of the (75/25 w/w) POM/ABS/clay nanocomposites revealed that, the major amount of clay silicates was dispersed selectively in the POM phase of the blend with an exfoliated morphology. The thermal stability of the (75/25 w/w) POM/ABS blend was increased with the increase in clay loadings. Differential scanning calorimetry (DSC) study suggested the enhancement in the non‐isothermal crystallization temperature of the matrix polymer in the blend/clay nanocomposites. The rheological study revealed a shear thinning behavior in the nanocomposites indicating good processability of the nanocomposites. The solvent uptake property of the blend was decreased in the presence of small amount of the clay in the nanocomposites. The tensile strength and Young modulus of the (75/25 w/w) POM/ABS blend were increased, whereas, percent elongation of the blend was decreased with increasing the clay content. The toughening effect of the ABS was prominent in the POM/ABS/clay nanocomposites compared to the pristine polymer. POLYM. COMPOS., 35:273–282, 2014. © 2013 Society of Plastics Engineers     

粘土/SBR/BIIR纳米复合材料的结构与性能

采用溴化丁基橡胶(BIIR)与粘土/SBR复合胶制备粘土/SBR/BIIR复合材料,并对其结构与性能进行研究.结果表明:粘土/SBR/BIIR并用胶为以BIIR为连续相、以SBR为分散相的海岛结构,并且粘土基本分散于SBR分散相中,所制备的复合材料为隔离型纳米复合材料;BIIR与SBR的相容性不好,热力学上基本不相容;...     

Novel morphologies of poly(phenylene oxide) (PPO)/polyamide 6 (PA6) blend nanocomposites

Poly(phenylene oxide) (PPO)/polyamide 6 (PA6) (50/50 w/w) blend nanocomposites were prepared by melt mixing of PPO, PA6, and organically modified clay. The morphology of PPO/PA6 nanocomposite with various amounts of clay has been investigated using scanning electron microscope (SEM), transmission electron microscope (TEM), and wide-angle X-ray diffraction (WAXD). For the PPO/PA6 blend without clay, PPO is dispersed in the PA6 matrix with an average particle diameter of about 4.2 μm. The domain size of the dispersed PPO phase is significantly decreased to about 1.1 μm by adding a small amount of clay (2%). However, when the amount of organoclay is more than 5%, the matrix-domain structure is found to transform into the co-continuous morphology. The TEM observation shows that all the organoclay is dispersed only in the PA6 phase with a high degree of exfoliation and there is no any clay detectable in the PPO phase for the nanocomposites regardless of the amount of clay. It is considered that the dispersed clay platelets play an important role in the control of the PPO/PA6 blend morphology. Firstly, the selective localization of clay in PA6 phase changes the viscosity ratio of the PPO and PA6 phases. Therefore, clay has significant effects on the morphology of the polymer blend. Secondly, the high aspect ratio of the clay platelets prevents the coalescence of domains during melt mixing.     

Comparative performance of carbon nanotube and nanoclay on thermal properties and flammability behavior of amorphous polyamide/SEBS blend

Multiwall carbon nanotubes (CNT) or montmorillonite clay (MMT-30B) were added to a poly(hexamethylene isophthalamide-co-terephthalamine) (an amorphous polyamide - aPA) and styrene-ethylene/butylene-styrene graphitized with maleic anhydride (SEBS) blend, in different concentrations, in order to investigate the morphology, thermal properties and flammability behavior. Different nanoparticle localizations in the phase blend were observed through transmission electronic microscopy. CNT nanoparticles are localized in SEBS phase, and MMT-30B nanoparticles in aPA phase. No significant changes were observed on transition temperatures and thermal stability with both nanoparticle additions. However, a slight increase on storage modulus for clay nanocomposites and a slight reduction for carbon nanotube nanocomposites were observed, due to their different phase localizations. Regarding flammability, CNT nanocomposites showed better performance as a flame retardant when compared to samples with MMT-30B. Although the MMT-30B nanocomposites could not be classified according to the UL-94 criteria, no dripped flaming particles were observed, due to the a char barrier formation on the polymer surface. The CNT nanocomposites were classified according to the UL-94 criteria as V-2. The CNT's selective localization on the SEBS phase decreases its heat-release rate, but no interconnected network structure was formed in the matrix to suppress the dripping flaming particles.     

Phase morphology and clay distribution of poly(trimethylene terephthalate)/polypropylene/montmorillonite nanocomposites

Poly(trimethylene terephthalate) (PTT)/polypropylene (PP) blend nanocomposites were prepared by melt mixing of PTT, PP, and organically modified clay. The phase morphologies of the PTT/PP nanocomposites and the distribution of the clay in the nanocomposites were investigated using scanning electron microscopy, transmission electron microscopy (TEM), and wide angle X‐ray diffraction. When PP is the dispersed phase, the domain size of the PP phase is decreased significantly with increasing the clay content from 0 to 5 wt %. In contrast, when PTT is the dispersed phase, the dimension of the PTT phase is a little larger in the presence of 2 wt % clay compared with the case of without clay. TEM observations indicate that the clay is mainly distributed at the phase interfaces along the phase borderlines. In addition, some intercalated clay tactoids (multilayer particles) are observed in the PTT matrix whereas no discernable clay particles can be found in the PP phase, indicating that the affinity of clay with PTT is higher than with PP. In the presence of 5 wt % PP‐graft‐maleic anhydride, the phase morphology is much finer, and most clay is exfoliated and distributed at the phase interfaces forming phase borderlines in polygonal shape. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Morphological evolution and mechanical property enhancement of natural rubber/polypropylene blend through compatibilization by nanoclay

Nanocomposites of natural rubber (NR)/polypropylene (PP) (80/20 wt %) blends filled with 5 phr pristine clay were prepared by melt‐mixing process. Effects of clay incorporation technique via conventional melt‐mixing (CV) and masterbatch mixing (MB) methods on nanostructure and properties of the blend nanocomposites were investigated. The XRD, SAXS, WAXD, and TEM results showed that the clays in the NR/PP blend nanocomposites were presented in different states of dispersion and were locally existed at the interface between NR and PP as well as dispersed in the NR matrix. The presence of clay caused unique morphological evolution such as fine fibrillar PP domains. The tensile strength was improved over the unfilled NR/PP blends by 53% and 224%, and the storage modulus at 25 °C was increased by 78% and 120% for the NR/PP/clay nanocomposites prepared by CV and MB methods, respectively. Significant improvement in both properties was particularly obtained from the MB method due to finer dispersion fibrillar PP phase in the NR matrix and stronger interfacial adhesion between NR and PP fibers, as suggested from DMA. The oil resistance of blend nanocomposites was also improved over that of the unfilled NR/PP blend, and this property was further progressed by the masterbatch mixing method. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44574.     

New poly(phenylene oxide)/polystyrene blend nanocomposites with clay: Intercalation,thermal and mechanical properties

We present the first study and results on the preparation and characterization of montmorillonite clay filler based polymer blend nanocomposites of the miscible poly(phenylene oxide)/polystyrene blend. Intercalated nanocomposites, prepared by a melt‐processing method with 2–6 wt % commercially available organically modified sodium montmorillonite, have been characterized with wide‐angle X‐ray diffraction, transmission electron microscopy analysis, thermal analysis (thermogravimetric analysis and differential scanning calorimetry), and mechanical tensile tests. We show that nanocomposites can be successfully prepared in a batch mixer at temperatures much below the conditions conventionally used for this blend without organic degradation. Thermal stability is enhanced by nanoscale hybrid formation. The level of intercalation (change in the d‐spacing) does not change with the clay loading. Better dispersion of clay in the blend matrix has been observed at a low level of clay content. The nanocomposites show improved tensile modulus (by 31%) in comparison to the blend, whereas the tensile strength (stress at break) and elongation decrease in the presence of the filler with an increase in the clay loading. The Halpin–Tsai model is able to predict the modulus of the nanocomposites in very good agreement with the experimental data. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Morphology and properties of nylon 6 and high density polyethylene blends in presence of nanoclay and PE‐g‐MA

In this study, we report the synergistic effect of nanoclay and maleic anhydride grafted polyethylene (PE‐g‐MA) on the morphology and properties of (80/20 w/w) nylon 6/high density polyethylene (HDPE) blend. Polymer blend nanocomposites containing nanoclay with and without compatibilizer (PE‐g‐MA) were prepared by melt mixing, and their morphologies and structures were examined with scanning electron microscopy (SEM) and wide angle X‐ray diffractometer (WAXD) study. The size of phase‐separated domains decreased considerably with increasing content of nanoclay and PE‐g‐MA. WAXD study and transmission electron microscopy (TEM) revealed the presence of exfoliated clay platelets in nylon 6 matrix, as well as, at the interface of the (80/20 w/w) nylon 6/HDPE blend–clay nanocomposites. Addition of PE‐g‐MA in the blend–clay nanocomposites enhanced the exfoliation of clays in nylon 6 matrix and especially at the interface. Thus, exfoliated clay platelets in nylon 6 matrix effectively restricted the coalescence of dispersed HDPE domains while PE‐g‐MA improved the adhesion between the phases at the interface. The use of compatibilizer and nanoclay in polymer blends may lead to a high performance material which combines the advantages of compatibilized polymer blends and the merits of polymer nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Free‐volume hole properties of two kinds thermoplastic nanocomposites based on polymer blends probed by positron annihilation lifetime spectroscopy

Two type of nanocomposites—an immiscible blend, high density polyethylene/polyamide 6 (HDPE/PA‐6) with organomodified clay, and a compatibilized blend, high density polyethylene grafted with acrylic acid/PA‐6 (PEAA/PA‐6) with organomodified clay—were prepared via melt compounding. X‐ray diffraction and transmission electron microscopy results revealed that the clay was intercalated and partially exfoliated. Positron annihilation lifetime spectroscopy has been utilized to investigate the free‐volume hole properties of two type of nanocomposites. The results show a negative deviation of free‐volume size in PEAA/PA‐6 blend, and a positive deviation in HDPE/PA‐6 blend, and I₃ has a greater negative deviation in compatibilized blend than in immiscible blend due to interaction between dissimilar chains. For nanocomposites based on polymer blends, in immiscible HDPE/PA‐6/organomodified clay system, the variation of free‐volume size with clay content is not obvious and the free‐volume concentration and fraction decreased. While in the case of compatibilized PEAA/PA‐6/organomodified clay nanocomposites, complicated variation of free‐volume properties due to interactions between two phases and organomodified clay was observed. And the interaction parameter β shows the interactions between polymers and organomodified clay. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2463–2469, 2006     

Polylactic acid/epoxidized palm oil/fatty nitrogen compounds modified clay nanocomposites: Preparation and characterization

Clay modification was carried out by treatment of fatty nitrogen compounds (FNCs); fatty hydrazide (FH), hydroxy methyl fattyamide (HMFA), and difatty acyl thiourea (DFAT) were synthesized from vegetable oils with a sodium montmorillonite (MMT) as natural clay. This process was accomplished by stirring the clay particles in an aqueous solution of FH, HMFA, and DFAT, by which the clay layer thickness increased from 1.23 to 2.69, 2.89 and 3.21 nm, respectively. The modified clay was then used in the preparation of the polylactic acid/epoxidized palm oil (PLA/ EPO) blend nanocomposites. The interaction of the modifier in the clay layer was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR). Elemental analysis was used to estimate the presence of FNCs in the clay. The nanocomposites were synthesized by solution casting of the modified clay and a PLA/EPO blend at the weight ratio of 80/20, which has the highest elongation at break. The nanocomposites were then characterized using XRD, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and tensile properties measurements. Improvement in mechanical properties of the FH-MMT, HMFA-MMT, and DFAT-MMT nanocomposites was obtained when 2% of the DFAT-MMT and 3% of both FH-MMT and HMFA-MMT loadings were used. PLA/EPO modified clay nanocomposites show higher thermal stability in comparison with those of the PLA/EPO blend. The XRD and TEM results confirmed the production of nanocomposites.