共查询到20条相似文献,搜索用时 176 毫秒
1.
于杰;胡世军;郭建兵;张敏敏;秦舒浩 《中国塑料》2010,24(3):49-54
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。 相似文献
2.
相容性聚合物共混物由于其优异的性能已成为新材料的主要研究方向。但许多共混物是互不相容的,因此必须改善它们的相容性。综述了聚合物共混物的相容性及各类增容剂的特点及应用。同时介绍了无机纳米粒子的引入对不相容聚合物共混体系相容性的影响。 相似文献
3.
4.
5.
6.
7.
8.
论述了聚合物共混体系/黏土纳米复合材料内部多相结构形态研究的最新进展;从共混聚合物基体对黏土的分散形态以及黏土对不相容共混基体相结构的影响两方面总结了多相形态的影响因素;探讨了相形态改善、反转的机理。 相似文献
9.
10.
在聚合物合金的制备过程中,主要是通过加入增容剂来改善聚合物合金相容性。早期普遍采用非反应型增容剂,而目前主要是以反应型增容剂为主。改变链结构、利用低分子量化合物、互穿网络技术等也是改善聚合物合金的常用办法。此外,无机纳米粒子对聚合物共混体系相容性也会产生一定影响。 相似文献
11.
Rigid inorganic filler has been long time used as a reinforcement agent for polymer materials. Recently, more work is focused on the possibility that using filler as a compatibilizer for immiscible polymer blends. In this article, we reported our efforts on the change of phase morphology and properties of immiscible polypropylene(PP)/polystyrene(PS) blends compatibilized with nano-SiO2 particles. The effects of filler content and mixing time on the phase morphology, crystallization behavior, rheology, and mechanical properties were investigated by SEM, DSC, ARES and mechanical test. A drastic reduction of PS phase size and a very homogeneous size distribution were observed by introducing nano-SiO2 particles in the blends at short mixing time. However, at longer mixing time an increase of PS size was seen again, indicating a kinetics-controlled compatibilization. This conclusion was further supported by the unchanged glass transition temperature of PS and by increased viscosity in the blends after adding nano-SiO2 particles. The compatibilization mechanism of nano-SiO2 particles in PP/PS blends was proposed based on kinetics consideration. 相似文献
12.
Thermoset/thermoplastic elastomer (TPE) blends of poly(propylene glycol) (PPG)-type epoxy resin (ER) and a diblock copolymer, polystyrene–b-polybutadiene (SB, with 30% styrene content), were prepared using 4,4′-diaminodiphenylmethane (DDM) as curing agent. The miscibility and thermal transition behavior of DDM-cured ER/SB blends were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The existence of three separate glass transitions, which are independent of the blend composition, indicates that SB is immiscible with DDM-cured ER. Neither the PS block nor the PB block exhibits miscibility with the cured ER. There exist three phases in the blends: a PS microphase, an ER-rich phase and a PB microphase. The phase structure and morphology of the ER/SB blends were studied using both scanning and transmission electron microscopy (SEM and TEM); a variety of morphologies were observed, depending on the blend composition. For the blends with 5 and 10 wt% SB, SB domains with irregular shapes and broadly distributed sizes are dispersed in a continuous cured ER matrix. For the blends with 20–60 wt% SB, interpenetrating bicontinuous phase structures are observed. For the blends with 70 wt% and more SB, a dispersion of cured ER particles in the SB matrix is obtained. The TEM observation showed that the two phases in the blends exhibit a good interfacial adhesion. The interfacial layer between the ER and SB phases varies from 100 to 300 nm for the blend with 20 wt% SB content, SB micelles are formed surrounding the SB domains in the ER matrix. Small-angle X-ray scattering (SAXS) experiments reveal that the SB diblock polymer still exhibits a lamellar microphase structure within the SB phase and the long spacing of lamellae nearly does not change in the blends. The SB diblock copolymer is microphase separated in the macroscopically phase separated ER/SB blends. 相似文献
13.
基于相转化法制备了复合微球载体负载的(n-BuCp)2ZrCl2/PSA/TiCl3复合催化剂。利用聚合物膜将两个传统的催化剂(茂金属和Ziegler-Natta催化剂)隔开,即先将Ziegler-Natta催化剂负载于无机载体上作为内核,随后将聚合物膜均匀沉积在无机载体催化剂表面,最后将茂金属催化剂溶液迅速负载于聚合物膜上,得到“内钛外茂”型(n-BuCp)2ZrCl2/PSA/TiCl3复合催化剂。在实验室条件下,模拟工业淤浆双釜串联反应工艺,在第一段反应中制备超高分子量(1.4×106 g/mol)高支化度的乙烯/1-己烯共聚物,在第二段反应中,制备低分子量低支化度的聚合物。调节两段反应的聚合时间,制备了不同组成的聚乙烯共混物。通过DSC和流变学的方法研究了聚乙烯共混物的共混性能,并与机械共混法得到的聚乙烯共混物的共混性质进行比较。 相似文献
14.
A novel mechanism to form binary polymer blends is through phase separation by spinodal decomposition in the unstable region of the phase diagram. The present work investigates the effects of thermally‐induced phase separation by spinodal decomposition on the morphology development of liquid crystalline polymer/polycarbonate blends. Moreover, a thermodynamic binary phase diagram is obtained using a twin‐screw extruder at various processing melt temperatures. Differential scanning calorimetry and scanning electron microscopy were used to study the miscibility of the blends and the resulting morphology. A thermodynamic binary phase diagram exhibiting a lower critical solution temperature was obtained. The droplet size distribution of the blend was also obtained and discussed in light of the Cahn‐Hilliard theory. 相似文献
15.
The effects of miscibility and blend ratio on uniaxial elongational viscosity of polymer blends were studied by preparing miscible and immiscible samples at the same composition by using poly(methyl methacrylate) (PMMA) and poly(acrylonitrile-co-styrene) (AS). Miscible polymer blend samples for the elongational viscosity measurement were prepared by using three steps: solvent blends, cast film, and hot press. A phase diagram of blend samples was made by visual observation of cloudiness. Immiscible blend samples were prepared by maintaining the prepared miscible samples at 200°C, which is higher than cloud points using a LCST (lower critical solution temperature) phase diagram. The phase structure of immiscible blends was observed by an optical microscope. The elongational viscosity of all samples was measured at 145°C, which is lower than the cloud-point temperature at all blend ratios. The elongational viscosity of PMMA and AS was similar to each other. The strain-hardening property of miscible blends in the elongational viscosity was only slightly influenced by the blend ratio, and this was also the case with immiscible blends. The strain-hardening property was only slightly influenced, whether it was miscible or immiscible at each blend ratio. Polydispersity in molecular weight for blend samples was not changed by GPC (gel permeation chromatography) analysis. Almost no change in the polydispersity of the molecular weight for blends and the similarity of elongational viscosity between PMMA and AS resulted in little influence of the blend ratio and miscibility on the strain-hardening property. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 757–766, 1999 相似文献
16.
Mauricio Gonzalez-Garzon Shant Shahbikian Michel A. Huneault 《Journal of Polymer Research》2018,25(2):58
This study examines the rheological, mechanical and thermal behavior of Poly(lactic acid)/Poly(methyl methacrylate) (PLA/PMMA) blends and takes a look at the phase structure evolution during their melt processing. Semi-crystalline or amorphous PLA grades were combined with PMMA of different molecular weight to prepare the blends. The rheological properties and phase structure was first assessed using small-amplitude oscillatory shear experiments. The blends were injection molded into bars and characterized in terms of their tensile properties and of their dynamic mechanical behavior. Differential scanning calorimetry was also used to study the miscibility and crystallization behavior of prepared blends. Tensile properties of the blends nearly followed a linear mixing rule with no detrimental effect that could have been associated with an uncompatibilized interface. However, dynamic mechanical analysis and calorimetric experiments showed that some phase separation was present in the molded parts. Nevertheless, a single Tg was found if sufficient time was given in quiescent conditions to achieve miscibility. The Gordon-Taylor equation was used to assess the polymer interactions, suggesting that miscibility is the thermodynamically stable state. The ability of PLA to crystallize was strongly restricted by the presence of PMMA and little or no crystallinity development was possible in the blends with more than 30% of PMMA. Results showed an interesting potential of these blends from an application point of view, whether they are phase separated or not. 相似文献
17.
L. G. Bourland 《乙烯基与添加剂工艺杂志》1988,10(4):191-199
Although polymer/polymer miscibility is considered the exception to the general rule, in polymer thermodynamics specific interactions between active sites on two polymers can be a driving force for polymer/polymer miscibility. Both the intermolecular interactions of the alpha hydrogen of PVC with carbonyl groups in various polyesters and the polarity of the chlorine bond have been claimed to promote miscibility. Both of these interactions are potential in PVC/styrene maleic anhydride (SMAnh) polymer blends. These specific interactions promoting miscibility and the resulting mechanical properties of these systems is the subject of this report. SMAnh (12.5% MA) copolymer was melt compounded with a stabilized PVC compound using a Haake Rheocord twin screw extruder. Test data generated for these blends were analyzed for miscibility and effects of SMAnh copolymers on heat resistance, fire retardance, impact strength, and processability of PVC. 相似文献
18.
The effect of varying interaction parameters on the phase diagrams of ternary polymer blends was explored by simulating spinodals through use of the Flory-Huggins lattice theory. Results indicate that miscibility is favored for the case of ternary mixtures of marginally miscible or marginally immiscible pairs where all pair interactions are nearly athermal. Miscibility is restricted for asymmetric ternary blends when one of the polymer pairs is either strongly miscible or strongly immiscible. For symmetric blends of partially immiscible pairs, both two-phase and three-phase miscibility gaps are predicted. 相似文献
19.
木质素与合成高分子共混的研究进展 总被引:2,自引:1,他引:2
根据文献资料,对木质素与不同合成高分子共混体系的性能、相容性和共混物分子间的氢键作用以及对相容性的影响进行了综述。根据木质素本身的特点,分析了木质素/合成高分子共混体系中的结晶性能、热稳定和光稳定性能以及抗氧化性能的变化。通过对文献的理解和数据的比较,对不同官能团、不同化学环境对木质素/高分子共混体系相容性的影响以及木质素在其晶区所起的作用作了深入的分析,并且对相容性较差体系中木质素种类、分子量和分子量分布对相容性及其它性能的影响进行了评述。 相似文献
20.
研究剪切流动下共混物相行为规律的实验方法 总被引:4,自引:2,他引:2
从实验原理、仪器设备、分析方法等方面,介绍了在开展剪切流动对共混物相行为影响研究中应用的实验方法,并着重介绍了包括应用最广泛的二维小角激光散射流变法在内的实时测试的各种实验方法,为不断改进和完善此类研究的实验手段提供了参考。 相似文献