基于DPD方法的PP/PA6二元体系混合相容性仿真分析

为了从分子角度分析聚丙烯(PP)、尼龙6 (PA6)二元体系的混合相容性,运用耗散粒子动力学(DPD)方法模拟了PP/PA6二元共混体系,并分析温度对PP/PA6共混性参数的影响。结果表明,PP与PA6在各个混合比条件下形成了不同的介观相形貌。当PA6含量上升后,体系中形成了聚集程度更高的PA6珠子。PP/PA6共混体系中都发生了同相富集的过程,导致PP/PA6共混物无法转变为均相体系,PP与PA6粒子表现出不同的密度曲线波动幅度。随着温度的不断上升,体系的介观相貌依然属于球状结构,并未形成不同的介观相; PP与PA6链的扩散系数也明显增大,表明当温度上升后链运动能力也随之增强,使体系获得更优的流动性;各共混体系的PP链均方根末端距都增大了,并且均方根末端距的上升幅度也受到PP/PA6混合比的显著影响。     

PP-g-GMA的制备及其增容PP/PA6共混物的性能

通过熔融接枝反应制备了甲基丙烯酸缩水甘油酯接枝聚丙烯（PP-g-GMA）,并将其作为聚丙烯/聚酰胺6（PP/PA6）共混物的相容剂,研究了PP-g-GMA对PP/PA6共混物的力学性能及形态结构的影响。结果表明,采用滴定法测得PP-g-GMA接枝率为3.35 %;当PP-g-GMA的添加量为4 %（质量分数,下同）和8 %时,PP/PA6/PP-g-GMA共混物的拉伸强度和缺口冲击强度分别较PP/PA6共混物提高了32.4 %和60.4 %;PP-g-GMA显著改善了PP/PA6 共混物的界面相容性,是PP/PA6共混物的有效增容剂。     

PP/PA6共混物的形态和流变性能

将聚丙烯（PP）和聚酰胺6（PA6）共混可以使PP和PA6在性能上互补，所得共混物性价比很高。本文分析了PP／PA6共混物在共混时相容性和流变，性对其形态的影响。列举了目前PP／PA6增容剂的研究情况，二相相容时的简单动力学模型，以及分散相PA的含量、增容剂的种类、双螺杆挤出机熔融段的螺杆结构、螺杆转速、共混方式等影响PP／PA6共混物形态的因素。     

POE-MAH对PA66/PP共混物形态结构和相容性的影响

通过扫描电镜（SEM）观察、差示扫描量热法（DSC）和广角X射线衍射分析（WAXD）,研究了POE－MAH对PA66／PP共混物的形态结构和相容性的影响。实验结果表明,POE－MAH的加入可使PA66／PP共混物由不相容的两结构向相容的均质网状结构转变,共混物的相容性和分散度得以提高,并在POE－MAH含量为9％时,其增容效果最好。随POE－MAH含量增加,PA66／66共混物的结晶度随之降低,同时共混物中PP的结晶行为及PA66和PP的微晶尺寸亦与POE－MAH含量相关。     

PP/EVOH/PA6共混物的性能研究

以聚丙烯接枝马来酸酐(PP-g-MAH)为相容剂,制备了聚丙烯(PP)/乙烯-乙烯醇共聚物(EVOH/)聚酰胺6(PA6)共混物,研究了PP/EVOH/PA6三元共混物的相容性、流变性能、阻隔性能、力学性能、热性能及形态结构。结果表明:相容剂与EVOH和PA6间发生了反应,提高了共混物的相容性;相容剂的加入提高了PP、EVOH、PA6的结晶温度,增强了PP与EVOH和PA6间的黏合力,降低了界面张力;EVOH占EVOH/PA6总量68%的三元共混物吸油率最小,当相容剂用量为5份时,PP/EVOH/PA6三元共混物吸油率比PP/EVOH二元共混物降低了8%。     

PP-g-MAH增容PP/PA 6的形态结构与流变性能

研究了用马来酸酐接枝聚丙烯（PP-g-MAH)来增容聚丙烯/聚酰胺6（PP/PA6）共混物的形态结构，探讨了PP-g-MAH增容PP/P6共混物的流动行为。结果表明，PP/PA6共混物为热力学不相容的海岛型两相结构，PP-g-MAH的加入改善了PA6与P宾相容性，使两相分散均匀。用PP-g-MAH为增容剂增容PP/PA6共混物，在加工成型温度下为非牛顿流体，在PP-g-MAH质量分数为10%，PP/PA6的配比为95：5-75：25，其流动行为可用T=1580γw^0.65模型描述。     

尼在6／聚丙烯共混体系研究进展

制备性能优良的尼龙6／聚丙烯（PA6／PP）共混物，需要解决的关键问题是PP在PA6树脂中的分解及界面相容性，年近来，PA6／PP相容性研究主要是引入第三组分作共混物的增容剂，综述了PA6／PP共混物的最新研究及发展趋势。     

尼龙6／聚丙烯共混体系研究进展

制备性能优良的尼龙 6 /聚丙烯 (PA6 /PP)共混物 ,需要解决的关键问题是PP在PA6树脂中的分散及界面相容性。近年来 ,PA6 /PP相容性研究主要是引入第三组分作共混物的增容剂。综述了PA6 /PP共混物的最新研究及发展趋势     

马来酸酐接枝物对PE/PA6共混物相容性的影响

采用熔融共混法制备了PP/PA6/POE-g-MAH和PP/PA6/PP-g-MAH共混物。通过扫描电子显微镜(SEM)、差示扫描量热(DSC)仪分析和力学性能测试研究了增容剂POE-g-MAH和PP-g-MAH对PP/PA6共混物相容性、形态结构和宏观力学性能的影响。结果表明,在PP/PA6共混体系中分别加入POE-g-MAH和PP-g-MAH不仅能显著改善两相界面的相容性,减小分散相的粒径,而且能使共混物的力学性能显著提高。当增容剂的用量为5份时,PP/PA6共混物有较好的综合力学性能。POE-g-MAH和PP-g-MAH增容PP/PA6共混体系非等温结晶行为的研究表明,POE-g-MAH和PP-g-MAH均能促进PA6对PP基体的异相成核作用。     

聚丙烯接枝衣康酸增容PA6／PP共混物性能及形态研究

采用反应型双螺杆挤出机和熔融接枝技术制备了一系列聚丙烯（PP）接枝物，包括单一单体接枝物PP接枝衣康酸（PP-g-ITA）和双单体接枝物PP接枝ITA和苯乙烯[PP-g-（ITA-co-St）]，通过红外光谱和热分析研究了PP接枝物的结构，并研究了PP接枝物的接枝率和熔体流动速率与单体和引发剂用量的关系。通过反应挤出制备了PP接枝物增容PA6／PP共混物，研究了增容共混物的力学性能和形态结构。结果显示：加入接枝物后，共混体系的冲击强度明显提高；SEM观察表明，接枝物的加入能明显改善增容共混物的两相界面结合状况，降低共混物的分散相尺寸，改善体系的分散状况，共混物的两相界面变得模糊，相容性得到明显提高；DSC测试表明，加入接枝物后，共混物中PA6组分的结晶度下降，PP组合的结晶度上升。表明PP-g-ITA是PA6／PP共混体系有效的增容剂兼增韧剂。     

A combined experimental and molecular dynamics simulation study on the miscibility of <Emphasis Type="Italic">Eucommia ulmoides</Emphasis> gum with butadiene rubber

The miscibility of Eucommia ulmoides gum (EUG) blended with butadiene rubber (BR) was investigated by atomistic molecular dynamics (MD), mesoscopic dynamics (MesoDyn) simulations and melt-mixing in an open two-roll mill at 80°C and 50 rpm. Seven EUG/BR blends (with weight ratios of 80/20, 70/30, 50/50, 30/70, and 20/80), as well as pure EUG and BR, were examined. Flory Huggins parameters, phase diagrams, the radial distribution function, free energy, and order parameters were computed for different blends using atomistic simulations to predict blend miscibility. The simulation results showed that all the EUG/BR blends have good miscibility. However, the mechanical properties of the vulcanized EUG/BR blends improved with the addition of EUG into BR matrix, and scanning electron microscopy (SEM) micrographs of the fractured surface had also revealed that the phase separation was not found, but which indicated EUG/BR had good miscibility. All the simulation results are qualitatively consistent with the experimental results, which demonstrates that the modeling strategies in this study may provide a powerful tool for predicting the miscibility and mesoscopic morphology of polymer blends.     

PP-g-MAH对PA6/PP共混体系性能的影响

以PP-g-MAH为相容剂,研究了PP-g-MAH对PA6/PP共混体系性能的影响。探讨了PP-g-MAH对PA6/PP共混物增容作用,提高共混物的各项性能指标。当PP-g-MAH为4份时,共混物的力学性能最好,当PA6/PP=90/10时,其力学性能有最大值;SEM照片显示,未加PP-g-MAH时,PP在PA6基体上分散不均,颗粒大,当加入适量的PP-g-MAH(4份)时,PP分散比较均匀,颗粒尺寸明显降低。以PP-g-MAH4份,PA6/PP=80/20制备的共混物,吸水率约是PA6的15%:冲击强度、热变形温度分别比PA6、PP提高了72%和106%,13.5℃和5.5℃。     

Multiscale molecular modeling in nanostructured material design and process system engineering

Atomistic-based simulations such as molecular mechanics, molecular dynamics, and Monte Carlo-based methods have come into wide use for material design. Using these atomistic simulation tools, we can analyze molecular structure on the scale of 0.1–10 nm. However, difficulty arises concerning limitations of the time and length scale involved in the simulation. Although a possible molecular structure can be simulated by the atom-based simulations, it is less realistic to predict the mesoscopic structure defined on the scale of 100–1000 nm, for example the morphology of polymer blends and composites, which often dominates actual material properties. For the morphology on these scales, mesoscopic simulations such as the dynamic mean field density functional theory and dissipative particle dynamics are available as alternatives to atomistic simulations. It is therefore inevitable to adopt a mesoscopic simulation technique and bridge the gap between atomistic and mesoscopic simulations for an effective material design. Furthermore, it is possible to transfer the simulated mesoscopic structure to finite elements modeling tools for calculating macroscopic properties for the systems of interest.In this contribution, a hierarchical procedure for bridging the gap between atomistic and macroscopic modeling passing through mesoscopic simulations will be presented and discussed. The concept of multiscale (or many scale) modeling will be outlined, and examples of applications of single scale and multiscale procedures for nanostructured systems of industrial interest will be presented. In particular the following industrial applications will be considered: (i) polymer-organoclay nanocomposites of a montmorillonite–polymer–surface modifier system; (ii) mesoscale simulation for diblock copolymers with dispersion of nanoparticels; (iii) polymer–carbon nanotubes system and (iv) applications of multiscale modeling for process systems engineering.     

Multiscale modeling for polymer systems of industrial interest

Atomistic-based simulations such as molecular mechanics (MM), molecular dynamics (MD), and Monte Carlo-based methods (MC) have come into wide use for materials design. Using these atomistic simulation tools, one can analyze molecular structure on the scale of 0.1–10 nm. Although molecular structures can be studied easily and extensively by these atom-based simulations, it is less realistic to predict structures defined on the scale of 100–1000 nm with these methods. For the morphology on these scales, mesoscopic modeling techniques such as the dynamic mean field density functional theory (Mesodyn) and dissipative particle dynamics (DPD) are now available as effective simulation tools. Furthermore, it is possible to transfer the simulated mesoscopic structure to finite element modeling tools (FEM) for calculating macroscopic properties for a given system of interest. In this paper, we present a hierarchical procedure for bridging the gap between atomistic and macroscopic modeling passing through mesoscopic simulations. In particular, we will discuss the concept of multiscale modeling, and present examples of applications of multiscale procedures to polymer–organoclay nanocomposites. Examples of application of multiscale modeling to immiscible polymer blends and polymer–carbon nanotubes systems will also be presented.     

Morphological properties,rheological behaviors,and phase interaction of nylon 11/polypropylene blends by in situ reactive compatibilization and dispersion through polyhydroxybutyrate

The current research discusses the reactive compatibilization of nylon 11 (PA11) and polypropylene (PP) using maleic anhydride grafted PP (PP-g-MA) through an extruder. PP phase is dispersed in PA11 by coalescence and droplet break-up mechanism by using polyhydroxybutyrate (PHB) as a dispersion agent that induces uniform interaction between the blend components. The reactive compatibilization ensures the mixing of polymers, and the consistent interaction of phases is controlled by dispersion. All of the blends were processed through melt processing at different compositions using a twin-screw extruder. Scanning electron microscopy was used to determine the morphologies of the binary and ternary blends. Surface tension and interfacial tension of the homopolymer characterizes the interaction of the polymers at interphase. The interaction of PHB/PA11 appeared preferable than that of PHB/PP, elaborating on the efficient dispersion and droplet formation of the PP phase. The compatibilizer maleic anhydride grafted PP (PP-g-MA) imparts a drastic effect on the compatibility of PA11-PP and PA11-PHB-PP blends and reduces PP phase particle size, which indicates the affinity of PHB and PP. The encapsulation of PP by PHB was seen in the expectation of minimum free energy models. The rheological measurements were used to understand the phase separation within blends. These measurements were also applied to understand the interaction between PA11-PP-PHB phases. The modulus values and viscosity ratio of the blends were measured to follow the chain relaxation in the melt. In the Cole–Cole plot, it was found that the reduction in PP phase size influences the relaxation of chains of blends.     

Ternary polymer blends of polyamide 6, polypropylene,and acrylonitrile‐butadiene‐styrene: Influence of multiwalled carbon nanotubes on phase morphology,electrical conductivity,and crystallization

Ternary polymer blends of 80/10/10 (wt/wt/wt) polyamide6 (PA6)/polypropylene (PP)/acrylonitrile‐butadiene‐styrene (ABS), PP/PA6/ABS, and ABS/PP/PA6 were prepared in the presence of multiwalled carbon nanotubes (MWCNTs) by melt‐mixing technique to investigate the influence of MWCNTs on the phase morphology, electrical conductivity, and the crystallization behavior of the PP and PA6 phases in the respective blends. Morphological analysis showed the “core–shell”‐type morphology in 80/10/10 PA6/PP/ABS and 80/10/10 PP/PA6/ABS blends, which was found to be unaltered in the presence of MWCNTs. However, MWCNTs exhibited “compatibilization‐like” action, which was manifested in a reduction of average droplet size of the dispersed phase/s. In contrast, a separately dispersed morphology has been found in the case of 80/10/10 ABS/PP/PA6 blends in which both the phases (PP and PA6) were dispersed separately in the ABS matrix. The electrical percolation threshold for 80/10/10 PA6/PP/ABS and 80/10/10 PP/PA6/ABS ternary polymer blends was found between 3–4 and 2–3 wt% of MWCNTs, respectively, whereas 80/10/10 ABS/PP/PA6 blends showed electrically insulating behavior even at 5 wt% of MWCNTs. Nonisothermal crystallization studies could detect the presence of MWCNTs in the PA6 and the PP phases. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Influence of nano silica hybrid expandable graphite on flammability,thermal stability,and mechanical property of polypropylene/polyamide 6 blends

Silica (SiO₂) nanohybrid expandable graphite (nEG) particles fabricated through one-step method are used as an efficient flame retardant for polypropylene (PP)/polyamide 6 (PA6) blends. The effect of nEG on the flammability, thermal stability, crystallization behaviors, and mechanical properties of PP/PA6 composites is investigated by using limit oxygen index (LOI), UL-94 test, cone calorimeter test (CCT), thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared, scanning electron microscopy, and mechanical tests. Compared with pure expandable graphite (EG), nEG improves the flame retardancy of composites. The results of LOI show that LOI of PP/PA6/nEG10 and PP/PA6/nEG15 composites are 26.0% and 27.2%, respectively. But the LOI values of PP/PA6/EG10 and PP/PA6/EG15 composites are 25.7% and 26.9%, respectively. The UL-94 test results show that PP/PA6/nEG10 composites reach V-1 level when the nEG content is only 10%. However, the PP/PA6 composites with 10% EG does not pass the UL-94 test. In addition, PP/PA6 composites with 15% nEG can reach V-0 level. The CCT results further show that nEG has a higher flame-retardant efficiency than pure EG for PP/PA6 blends. The thermal stability of PP/PA6/nEG composites is better than that of PP/PA6/EG composites. The mechanical property tests indicate that nEG is more conducive to maintain the tensile and impact strengths of PP/PA6 blends than EG due to the enhanced compatibility and interfacial adhesion.     

Novel approach for the preparation of a compatibilized blend of nylon 11 and polypropylene with polyhydroxybutyrate: Mechanical,thermal, and barrier properties

This article comprises of the interaction in the immiscible polymer system of nylon 11 (PA 11), polypropylene (PP), and polyhydroxybutyrate (PHB). Reactive compatibilization extrusion method with maleic anhydride-grafted polypropylene (PP-g-MA) is used to achieve compatibility within the polymer. To further improve the interaction of the blend at interphase, PHB was added as a dispersive phase in a concentration varying from 10 to 40% of the total batch. Addition of PHB motives the excellent dispersion of PP chain in PA 11 and assures the compatibility between the phases of PA 11 and PP-g-MA. The entire system of tertiary and binary phases was blended in a twin-screw extruder at different composition. The macro-optimal tensile strength, Young's modulus, bending strength, and notched impact strength of PA11/PP systems were found to be superior as compared to their noncompatibilized systems. The degradation temperature of the blends of PA11/PP and PA11/PHB/PP with and without compatibilizer was evaluated by thermogravimetric analysis (TGA). It was found that the high temperature of degradation was required for compatibilized ternary blend than that of the compatibilized binary blend. The distortion temperature of the systems was studied with the help of heat deflection temperature (HDT) and found to be advanced for blend having a higher concentration of the dispersed phase. Differential scanning calorimetry (DSC) was used to determine the % crystallinity, melting, and crystallization temperature of this system. Chemical resistance and barrier properties of the different compatibilized and noncompatibilized blends were studied. PHB dispersed phase with a reactive compatibilizer cause enhancement in chemical resistance and barrier properties of the blend. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48152.     

添加PA66－MPP提高PP／GF增强塑料力学性能的研究

本文研究ＰＰ／ＧＦ（玻纤增强聚丙烯）的加工过程中，添加ＰＡ６６（尼龙）、ＭＰＰ（ＰＰ－ｇ－ＭＡＨ）进一步促进ＧＦ对ＰＰ的增强作用。考察了ＭＰＰ对ＰＰ／ＰＡ６６共混物的增容作用，ＰＡ６６、ＭＰＰ的组成配比对ＰＰ／ＧＦ增强塑料力学性能和微观结构的影响。结果表明：ＰＡ６６、ＭＰＰ的组成比对ＰＰ／ＧＦ的力学性能影响较大；较佳配比的ＰＡ６６、ＭＰＰ，可大幅度地提高增强塑料的力学性能。