Phase Morphology and Thermal Characteristics of Binary Blends Based on PTT and PA12

Summary Phase morphology, miscibility and thermal properties of a binary blend, poly- (trimethylene terephthalate) (PTT) / polyamide-12 (PA12), were examined and found to be immiscible showing a phase-separated morphology. DSC cooling data of the blends indicates that the melt crystallinity of PTT phase increases, with respect to pure state, upon blending with PA12 while that of polyamide phase declines in the presence of PTT phase implying that polyester molecules reduces the crystallization ability of polyamide phase. Also, PA12 in that blend where it is minor phase shows a fractionated crystallization. A significant cold crystallization exotherm supposed to be due to the reorganization of polymeric chains was exhibited by PTT phase in DSC second heating thermograms which its degree was raised upon blending with PA12. DMA graphs reveal a single tan peak due to the fact that the glass transition of the respective constituents overlap and a single peak comes into view. Therefore, DMA can not be solely used to assess the miscibility in this system.     

Morphology and Mechanical Properties in Polymer Blends of Photocurable Polymer and Polycarbonate

Relationships between the morphologies and mechanical properties of binary blends of a photocurable polymer (2‐propenoic acid, (octahydro‐4,7‐methano‐1H‐indenediyl) bis(methylene)ester; DCA) and a linear polymer (poly(4,4′‐cyclohexylidene bisphenol carbonate); PCz) have been investigated. The blend films are prepared by in situ photopolymerization of homogeneous mixtures of a DCA‐monomer and PCz. The phase structure has been converted from a semi‐interpenetrating polymer networks (semi‐IPN) structure to a bicontinuous structure by controlling the cure temperature. Bicontinuous phase‐separated structures can be obtained by curing a wide range of compositions of 17–50 wt.‐% PCz at high temperatures. Miscible semi‐IPN structures are attained by means of photopolymerization below the glass transition temperature of the homogenous mixture before performing photoirradiation, such that magnetic relaxation measurements showed the blend to be miscible in the 10 nm order. The tensile strength and modulus reached a maximum in those blends having an intermediate vague phase structure between semi‐IPN and bicontinuous structures that have a strong interfacial interaction, which leads to incomplete phase decomposition in the PCz‐rich matrix phase. The maximum strength and modulus prepared under optimum condition are inferior to those of the individual components. In contrast, the elongation and break energy are greatly improved in those blends with bicontinuous structures having a diffused phase boundary.

DCA‐rich domain size in bicontinuous structure for DCA/PCz system, as a function of cure temperature; (□) 17 wt.‐% PCz, (○) 30 wt.‐% PCz, and (?) 50 wt.‐% PCz.     

The Compatibilizing Effects of Epoxy Oligomers on Blends of Thermoplastics and Thermotropic Liquid Crystalline Polymer

Abstract:

Several epoxy oligomers, A-X-A series, in which the A represents epoxy group, and the X is molecular block between epoxy groups, were synthesized or selected to compatibilize the blends of polysulfone (PSF)/a semiaromatic Thermotropic Liquid Crystalline Polymer (TLCPA1) and the blends of polycarbonate (PC)/TLCPA1. The results of Differential Scanning Calorimetry (DSC), Scanning Electronic Microscopy (SEM), and mechanical properties measurement of these compatibilized blends showed that the compatibilizing effects of these epoxy oligomers relied on the structure and the spacing block length of X. Among them, one new epoxy oligomer, which was made from allyl bisphenol-A and E-44 (a bisphenol-A epoxy resin, epoxy equivalent: 230), has been demonstrated to be a highly efficient compatibilizer for PSF/TLCPA1 blends. Adding 2% of this compatibilizer to PSF/TLCPA1 blend led to a 6.7% and 9.7% increase of bending strength and tensile strength, respectively.     

Study on Energy Ratio Model for Phase Morphology of Immiscible Polymer Blends

The formulas of polymer melt velocity, shearing rate, and shearing stress in simple shearing flow under the vibration force field were established. Based on the concept of an energy ratio model, the rate of energy dissipation and the energy ratio for blending systems are expressed theoretically. The calculated and analytical results of both the dynamic flow field and energy ratio show that with the increasing of vibration strength the fluctuating shearing force field exerted on polymer melt and the negative pressure diffusion behavior of instantaneous impulse strengthen. The energy consumption for phase inversion of immiscible polymer blends under the vibration force field is less than that of steady state. The parameter controllability of the vibration force field provides a more effective method for realizing phase inversion of immiscible polymer blends.     

PTT／PET共混体系结晶行为和形态研究

利用差示扫描量热仪、正交偏光显微镜研究了聚对苯二甲酸丙二醇酯(PTT)、聚对苯二甲酸乙二醇酯(PET)及PTT/PET共混体系(质量比为25∶75)的结晶行为、形态和等温结晶动力学。结果表明,PTT/PET共混物中,少量的PTT部分地起到了成核作用,但在一定程度上阻碍了PET链段规则地进入晶格,影响了结晶速率。偏光显微镜观察到PET、PTT和PTT/PET共混物在120℃下1、20min的溶液滴膜有较清晰的球晶。     

PTT/mPE共混物的制备和性能研究

研究了聚对苯二甲酸丙二酯(PTT)/茂金属聚乙烯(mPE)共混体系的流变性能、结晶熔融行为、力学性能以及增容剂对共混物相形态的影响。结果表明：PTT/mPE共混物熔体为假塑性流体,熔体表观黏度随PTT含量的增加而迅速降低,PTT含量高于40％时共混物表观黏度迅速下降,PTT含量越多对温度变化的敏感性越强。PTT和mPE可分别结晶,但PTT组分的结晶峰温度Tpc和结晶熔融峰温度Tm均比纯PTT的明显提高,而mPE组分的Tpc和Tm与纯mPE的相近,mPE可以促进PTT熔体结晶,但已经形成的PTT晶体不影响mPE的结晶,mPE的结晶行为主要发生在mPE微相区内。增容剂马来酸酐接枝乙丙橡胶提高了PTT与mPE间的相容性,共混物的冲击强度随着增容剂的增加而提高,mPE和增容剂共同发挥了增韧作用。     

m-LLDPE/nano-SiO2复合材料的性能和形态结构研究

采用沉降法对纳米SiO2进行表面处理,用熔融共混法制备了m-LLDPE/纳米SiO2复合材料.研究了该复合材料的力学性能和光学性能.结果表明：随着纳米SiO2的加入,其复合材料的缺口冲击强度和拉伸强度呈峰形变化,断裂伸长率略有下降.当加入少量的纳米SiO2后,复合材料的红外线吸收能力较m-LLDPE明显提高;此外,m-LLDPE/纳米SiO2复合材料的可见光透过率有所降低,雾度却有明显的先上升后下降趋势     

m-LLDPE/nano-SiO_2复合材料的性能和形态结构研究

采用沉降法对纳米SiO2进行表面处理,用熔融共混法制备了m-LLDPE/纳米SiO2复合材料。研究了该复合材料的力学性能和光学性能。结果表明:随着纳米SiO2的加入,其复合材料的缺口冲击强度和拉伸强度呈峰形变化,断裂伸长率略有下降。当加入少量的纳米SiO2后,复合材料的红外线吸收能力较m-LLDPE明显提高;此外,m-LLDPE/纳米SiO2复合材料的可见光透过率有所降低,雾度却有明显的先上升后下降趋势。通过SEM得出,表面处理对纳米SiO2在基体中的分散性有显著的改善。     

长链型超支化聚合物对PLA/PPC共混体系的增容改性研究

将“一步法”合成的超支化聚酯进行接枝改性,得到末端带有大量脂肪酸长链的超支化聚合物（长链型超支化聚合物,LCHBP）,并采用红外光谱、核磁共振、羟值滴定等方法对其进行表征。以LCHBP为改性剂,对聚乳酸（PLA）/聚碳酸亚丙酯（PPC）进行不同程度的改性,制备了PLA/PPC/LCHBP熔融共混物,采用差示扫描量热仪、电子万能试验机、扫描电镜等,对其热性能、力学性能、断面形貌等进行表征。结果表明,加入不同含量的LCHBP后,共混体系的ΔTg出现不同程度降低,表明LCHBP的加入改善了PLA与PPC的相容性;与PLA/PPC体系相比,LCHBP的加入可使共混体系在保持拉伸强度基本不变的情况下,大幅提升断裂伸长率和冲击强度,其中当LCHBP的加入量为2.0 %时,冲击强度提高61 %,断裂伸长率提高367 %。     

Correlation of Morphology and Viscoelastic Properties of Partially Biodegradable Polymer Blends Based on Polyamide 6 and Polylactide Copolyester

The morphology and viscoelastic properties of newly prepared partially biodegradable polymeric blend based on polyamide 6 and commercially available co-polyester of polylactide, BioFlex®, were studied in this work. Observations by scanning electron microscopy and solvent extraction method, and rheological measurements were carried out for structural studies. Experimental data were compared with several semi-empirical models for determination of phase inversion concentration. The correlation between experimental data and models reveals the significant contribution of elasticity effect to interfacial adhesion between polyamide 6 and BioFlex, which seems to have influence on the phase inversion composition of the blends and co-continuous morphology formation.     

双亲嵌段聚合物的合成及在共混体系中的增容作用

主要介绍了以活性阴离子聚合法和原子转移自由基聚合法合成双亲嵌段聚合物的方法、特点和影响因素,另外对双亲嵌段聚合物在聚合物共混体系中的增容作用作了评述。     

PTT/PE共混体系结品动力学及结晶形态研究

采用差示扫描量热法(DSC)研究了聚对苯二甲酸乙二醇酯/聚乙烯(PTT/PE)共混体系的非等温结晶动力学,通过热台偏光显微镜(POM)对共混物在等温条件下的结晶形态进行了研究.结果发现:PTT/PE共混体系各样品的结晶峰温度随着冷却速率的提高而下降,而半结晶时间t1/2随着冷却速率的提高而提高;结晶动力学常数Zc随着冷却速率的提高而下降,表明共混体系的结晶速率随着冷却速率的提高而降低;在POM观察的时间范围内各样品的球晶尺寸随着时间的延长而增大,PTT/PE(30/70)共混体系在190℃结晶时,球晶尺寸较大,即球晶生长较快.     

PET/PTT共混体系的相容特性及力学性能研究

通过熔融共混法制备了聚对苯二甲酸乙二醇酯(PET)与聚对苯二甲酸醇酯(PTT)的共混物,采用差示扫描量热仪、动态热机械分析仪、万能电子试验机等对共混体系的热性能、动态力学性能及拉伸性能进行了测试。测得PET/PTT共混体系只有1个玻璃化转变温度(Tg)和损耗峰,表明在非晶区完全相容,其中纯PET的Tg为84℃,纯PTT的Tg低于50℃; 而双重熔融峰及热结晶峰宽化现象的出现表明,共混体系在晶区是部分相容,各组分倾向于分别进行有序化排列、单独结晶,其中纯PET的熔点为256℃,纯PTT的熔点为229 ℃;共混体系的拉伸模量和拉伸强度随PTT含量的增加呈上升趋势;但当共混比例接近时体系的拉伸模量和拉伸强度有所下降,共混比为5/5时的拉伸模量和拉伸强度分别低达1098MPa和51MPa。     

Polypropylene Blends with m-EPR Copolymers: Structure,Morphology and Thermal Properties

The effects of different contents of two metallocene propylene-based m-EPR elastomers on structure, morphology, thermal, and dynamic mechanical properties of the isotactic polypropylene/m-EPR blends were investigated. The both m-EPR copolymers have been built in isotactic polypropylene matrix as amorphous phase. However, the nucleation effect at lowest addition (2.5?vol%) and the solidification effect along with increased m-EPR’s additions have caused changes of the crystallinity degree and the size of spherulites in the isotactic polypropylene matrix. Higher degree of miscibility/compatibility of the isotactic polypropylene/m-EPR2, with lower viscosity has been observed. Homogeneous dispersion of m-EPR particles as well as their radial distribution has been observed.     

Effects of Compatibilizers on Morphology and Properties of Polyoxymethylene/Polypropylene Blends

The effects of polypropylene-graft-maleic anhydride compatibilizer on the mechanical thermal and morphological properties of polyoxymethylene/polypropylene blends were investigated. Polyoxymethylene/polypropylene blends with and without polypropylene-graft-maleic anhydride compatibilizer were prepared by an internal mixer. The morphology of polyoxymethylene/polypropylene blends clearly demonstrated a two-phase separation of dispersed phase and the matrix phase and the addition of polypropylene-graft-maleic anhydride changed the morphological characteristics of blends. Polyoxymethylene/polypropylene blends showed the decrease of mechanical properties with increasing of polypropylene content. The addition of polypropylene-graft-maleic anhydride improved Young’s modulus and storage modulus of polyoxymethylene/polypropylene blends. The incorporation of polypropylene improved the degradation temperature of polyoxymethylene.     

加工方法和分散相组成对PP／HDPE／m-LLDPE三元共混物形态和性能的影响

采用两种加工方法制备了PP/HDPE/m-LLDPE三元共混物,改变两种分散相m-LLDPE和HDPE用量,研究了其对不同加工方法制备的三元共混体系形态和性能的影响.结果表明,当m-LLDPE质量分数低于15%时,三元体系中分散相HDPE与m-LLDPE出现单独分散与包覆结构并存的形态,共混方法对材料的形态和力学性能影响不大;当m-LLDPE质量分数高于15%时,加工方法一制得的样品的冲击强度大幅提高,其内部包覆结构与单独分散的形态并存;加工方法二制得的样品中m-LLDPE与HDPE趋向于形成包覆结构.     

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。     

Preparation and Assessment of Phase Morphology,Rheological Properties,and Thermal Behavior of Low-Density Polyethylene/Polyhexene-1 Blends

In this work, polyhexene-1 (PH-1) is synthesized by polymerization of hexane-1 with Ziegler–Natta catalyst and melt blended with low-density polyethylene (LDPE). The phase morphology, rheology, crystallization, and thermal behavior of (LDPE)/PH-1 blends are investigated. A good compatibility is observed in the blends up to 10?wt% PH-1 and the most of the droplets in the fractured surface are covered with and buried in the LDPE matrix and at higher percentage the droplet particle size significantly increased. The effect of microstructure of the blends on the flow behavior is studied by small amplitude oscillation rheology. By decreasing the compatibility and increasing the particle size, the Cole–Cole plots are deviated from the semi-circular shape at higher percentages than 10?wt% of PH-1. The change in the crystallization and melting behavior of LDPE in the blends are studied by differential scanning calorimetry and X-ray diffraction (XRD). It is found that by increasing the PH-1 the melting temperature of LDPE decreased from 112.5 to 110.8°C and crystallization temperature increased from 95.2 to 97.7°C which is evident of the nucleation effect. The intensity of (110) peak in XRD test declined as a remake of amorphous part of LDPE and the degree of crystallinity of LDPE decreased from 28 to 22% at 20?wt% PH-1.     

Morphology in Immiscible Polymer Blends During Solidification of an Amorphous Dispersed Phase under Shearing

Solidification under shear of dispersed polycarbonate (PC) fibers in copolymer polyethylene‐methyl acrylate matrix (EMA) was investigated using a hot optical shear device. First, the deformation of PC droplets and its modeling under isothermal conditions were studied for comprehension purposes. Overall agreement with literature models was found and the main influence of the viscosity ratio has been stressed. Second, the morphology control through dynamic quenching was experimented. It consists of solidifying the amorphous PC dispersed phase under shear flow. Break‐up times of PC fibers were taken into account. Shear rate and quenching‐time balance was demonstrated. Thus, during dynamic solidification, a fibrillar morphology could be obtained through rapid quenching. Long quenching times allow nodular morphology, whose size depends on the shear rate used. PC rods can be obtained by adjusting the shear rate during dynamic quenching.     

The Influence of Chemical Topology on Morphology,Elastic and Rheological Properties of Rubber-Reinforced Polymer Blends

Abstract

Blends of random polystyrene-SBR were prepared first in a co-rotating twin screw extruder and then injected for being used as impact modifiers. Several experiments were realized, changing the chemical composition of SBR. The blends were made with 5% of SBR in a rigid matrix of polystyrene and the SBRs had different compositions. The samples were characterized by different techniques and compared to a sample with 0% SBR content. The tests performed were: a) mechanical: tensile strength, flexion and Izod impact; b) rheological: melt index flow and melt index razor-sharp at 205 °C and c) morphology: studied by scanning electron microscopy (SEM). The results show that the morphology of surfaces and the mechanical and rheological properties of these blends depend on the relation Styrene/Butadiene and on the structure of the SBRs.