Transmission electron microscopy study of phase morphology in polypropylene/ethylene-octene copolymer blends

Blends of polypropylene (PP) and ethylene-octene copolymers (EOC) were investigated by transmission electron microscopy (TEM) and by differential scanning calorimetry (DSC). The EOC contained 28, 37, 40 or 52 wt% of octene. Only the 50/50 PP/EOC ratio was used for all blends. None of the blends was fully miscible, there was always two-phase morphology. TEM observation followed by image analysis by ImageJ software revealed that the largest particles were in blend containing EOC-28 and the smallest were in blend with EOC-52. The coarsening rate at 200 °C was evaluated by TEM. The glass transition temperature (T_g) shift indicated partial miscibility. Partial miscibility was then confirmed by direct observation of bright PP lamellae in EOC dark phase.     

共聚物混溶性热力学-分子内排斥作用与附加共聚焓

基于聚合物分子间物理相互作用和统计平均场理论,引入附加共聚焓定义,使聚合物分子间的作用得到量化,同时推导出二元共混体系相互作用参数和三元共混体系混合焓关系式.利用所导出的公式解释一些常见聚合物共混体系和增溶体系.导出的关系式很好地解释了聚合物的热力学混溶性,但不能解释聚合物共混增溶作用.     

Synthesis of poly[(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate‐co‐ethyl acrylate] by incorporation of carbon dioxide into epoxide polymer and the miscibility behavior of its blends with poly(methyl methacrylate) or poly(vinyl chloride)

This study was related to the investigation of the chemical fixation of carbon dioxide to a copolymer bearing epoxide and the application of the cyclic carbonate group containing copolymer‐to‐polymer blends. In the synthesis of poly[(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate‐co‐ethyl acrylate] [poly(DOMA‐co‐EA)] from poly(glycidyl methacrylate‐co‐ethyl acrylate) [poly(GMA‐co‐EA)] and CO₂, quaternary ammonium salts showed good catalytic activity. The films of poly(DOMA‐co‐EA) with poly(methyl methacrylate) (PMMA) or poly(vinyl chloride) (PVC) blends were cast from N,N′‐dimethylformamide solution. The miscibility of the blends of poly(DOMA‐co‐EA) with PMMA or PVC have been investigated both by DSC and visual inspection of the blends. The optical clarity test and DSC analysis showed that poly(DOMA‐co‐EA) containing blends were miscible over the whole composition range. The miscibility behaviors were discussed in terms of Fourier transform infrared spectra and interaction parameters based on the binary interaction model. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1472–1480, 2001     

聚氧化乙烯/苯乙烯-马来酸钠共聚物共混体系性能研究

用热分析（DSC、TG）和FTIR对聚氧化乙烯（PEO）/苯乙烯-马来酸钠（St-alt-MANa,简称SMANa)共聚物共混体系的相容性、分子间作用、热失重等性质进行了研究。结果表明,共混物可以任意比互溶,它们之间的相互作用是PEO的醚键“-O-”和共聚物盐中的“-COOH”之间形成了氢键。TG分析结果表明,随温度的升高,首先形成了酸酐,这可由FTIR光谱确定。热降解产如CO2作为酸酐和共聚物中羧基的降解产物。与不饱和结构相关的谱带（1774cm^-1、1449cm^-1)在350℃和450℃的红外光谱中可观察到,这可能是主要的碳-碳链断裂的结果。共混体系的Tg随SMANa含量的增加而增加,而体系结果温度Tc、熔融温度Tm却略有下降,这说明两组分间具有良好的溶混性。     

PMMA/PC Blends: Effect of Mixing Conditions on Compatibility

In this work the effect of melt mixing condition and of a trans-esterification catalyst on miscibility of poly(methyl methacrylate) (PMMA)/polycarbonate of bisphenol A (PC) blends is studied. In particular, at high temperature chemical reactions between PMMA and PC phases can take place; these strongly change the compatibility in the blend and materials having single T_g can be obtained. FT-IR analyses, coupled with solvent extraction, suggest that a grafting reaction of PC on PMMA is involved. SEC and DSC data are consistent with spectroscopic results, and some decrement of the molar weight distribution (MWD) of PC phase is observed. On the other hand, the presence of a fraction of modified material having higher MWD of starting PMMA is also noticed. The single T_g characteristic of some materials has been confirmed by experimental data of structural relaxation performed by differential scanning calorimetry (DSC). These materials showed optical clarity and the morphological analysis performed by scanning electron microscopy (SEM) confirm the homogeneity of these materials.     

Fabrication of polyurethane binders grafted with functional reactive plasticizers by a catalyst-free click reaction

The design of nonmigratory energetic plasticizers with low sensitivity and high performance is of great significance but challenging. Herein, two nonmigratory norbornane-based reactive plasticizers (NRPs) are attached covalently to poly(glycidyl azide-co-tetrahydrofuran) (PGT)-based polyurethanes (PUs), offering a reliable, self-stable, and alternative energy source originating from ring strain, while mitigating the dangers to the environment by preventing migration. A binary mixture of PGT and NRPs is thermodynamically miscible up to 50/50 w/w. The catalyst-free click reactivity of the NRPs toward PGT evaluated by the activation energy is verified by calculating the frontier molecular orbital energy levels. The absent weight loss of the pure NRPs evident from the measured thermal stability of the NRP/PGT-based PU binders indicated that the NRPs react completely with the PGT matrix. The tensile properties of the PGT-based PU binder by the inclusion of NRPs increased with increasing NRP content because of the increased number of triazole groups and the norbornane moiety. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 402–411     

Numerical simulation of thermo‐solutal‐capillary migration of a dissolving drop in a cavity

In the present paper the thermo‐solutal‐capillary migration of a dissolving liquid drop, composed by a binary mixture having a miscibility gap, injected in a closed cavity with differentially heated end walls, is studied. The main goal of the analysis is to clarify if and how the drop migration is affected by the dissolution process. The numerical code is based on a finite volume formulation. A level‐set technique is used for describing the dynamics of the interface separating the different phases. A thermodynamic constraint fixes the concentration jump between the interface sides. This jump, together with that of the concentration normal derivatives, in turn defines the entity of the dissolution cross‐flow through the interface and the interface velocity relative to the fluid. Since the jump singularity of normal derivatives cannot be easily mollified, while retaining the necessary accuracy, a scheme for the species equation is elaborated that allows sharp jumps and has subcell resolution. Steady migration speeds are determined after the start‐up phase for different radii and temperature differences. The results will be used for the preparation of a sounding rocket space experiment. Copyright © 2003 John Wiley & Sons, Ltd.     

共混聚合物辐射效应研究的进展

本文综述了近十几年来国内外共混聚合物辐射效应研究的进展情况.内容包括辐射交联理论在共混聚合物体系中的适用性、共混体系的相容性、相态结构对辐射效应的影响及共混组份间的辐射敏化及保护效应等.     

Effect of crosslinking on intermolecular interactions in thermosetting blends of epoxy resin with poly(ethylene oxide)

The miscibility and intermolecular-specific interactions in thermosetting blends of epoxy resin (ER) with poly(ethylene oxide) (PEO) cured with various amounts of 1,3,5-tridroxybenzene (THB) were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The glass-transition behavior indicated that all the blends were miscible and had homogeneous amorphous phases; FTIR showed that there were the intermolecular hydrogen-bonding interactions between crosslinked ER and PEO. However, both the glass-transition behavior and infrared spectroscopy also indicated that the intermolecular interactions were significantly reduced by the formation of crosslinked structures, which was shown by comparing the experimental results of poly(hydroxyether of bisphenol A) (PH)/PEO and ER/PEO blends cured with various amounts of the curing agent. In ER/PEO blends the intermolecular hydrogen-bonding interactions were much weaker than the self-association of hydroxyls of ER, which was in marked contrast to the interactions in PH/PEO blends. In ER/PEO blends with various amounts of the curing agent, the intermolecular interactions between epoxy polymers and PEO were reduced with an increasing degree of crosslinking. The results were interpreted in terms of the effect of crosslinking on the intermolecular interactions, such as steric shielding, the screening effect, and chain connectivity resulting from the formation of the three-dimensional crosslinked network, which could reduce the intermolecular hydrogen-bonding interactions among hydroxyls of ER versus ether oxygen atoms of PEO. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2567–2575, 2004     

Poly（L—lactide）—Poly（ethylene glycol） Multiblock Copolymers：Synthesis and Properties

Poly (L-lactide)-poly (ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as better miscibility between the two components, low crystallinity and better hydrophilicity, which can be modulated by adjusting the block lengths of the two components.