Dynamically vulcanized acrylonitrile–butadiene–styrene terpolymer/nitrile butadiene rubber blends compatibilized by chlorinated polyethylene

Thermoplastic vulcanizates (TPVs) based on acrylonitrile–butadiene–styrene (ABS)/nitrile butadiene rubber (NBR) blends were prepared by dynamic vulcanization and then compatibilized by chlorinated polyethylene (CM). The effects of CM compatibilizer on the mechanical properties, Mullins effect, and morphological and dynamic mechanical properties of the TPVs were investigated systematically. Experimental results indicated that CM had an excellent compatibilization effect on the dynamically vulcanized ABS/NBR TPVs. Mullins effect results showed that the compatibilized ABS/NBR TPV had relatively lower internal friction loss than the ABS/NBR TPV, indicating the improvement of elasticity. Morphology studies showed that the fracture surfaces of ABS/CM/NBR TPVs were relatively smoother, indicating the improved elastic reversibility. DMA studies showed that the glass to rubber transition temperatures of ABS and NBR phases were slightly shifted toward each other with the incorporation of CM compatibilizer, which indicates the improvement of the compatibility. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40986.     

Rheology and morphology study of immiscible linear low‐density polyethylene/poly(lactic acid) blends filled with nanosilica particles

The objectives of this study are to investigate the effect of silica nanoparticles on the morphology and rheological behavior of immiscible linear low‐density polyethylene/poly(lactic acid) (LLDPE/PLA) blends. Melt blending method is applied to prepare the blends and their nanocomposites. Scanning electron microscope and parallel plate rheometer were used to investigate morphology and rheological behavior of the blend nanocomposites. Scanning electron microscope results demonstrated a significant change in morphology behavior by incorporation of silica nanoparticles. A significant reduction in the PLA droplet for LLDPE/PLA (75/25) with 8 wt % silica was observed. The rheological studies illustrated that for all samples storage modulus and complex viscosity of blend nanocomposites are higher than neat blends. Finally, melt rigidity of blend nanocomposites was estimated by measurement of rheological properties using a rotational rheometer through small amplitude oscillatory shear experiments. As a result, through the shear data, a high value quantity as a criteria for melt rigidity is obtained for the LLDPE/PLA (75/25) with 8 wt % silica in comparing to the other samples. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45526.     

Effect of starch ratio and compatibilization on the viscoelastic behavior of POE/starch blends

In this research, polyolefin elastomers (POE)/starch blends were prepared using an internal mixer with 0 to 55 wt% starch content, and MAH was added into POE/starch blend to prepare a composite that improves its biodegradation, while tuning the viscoelastic behavior and morphology. The effect of the composition and the compatibilizer addition on properties, such as morphology, rheology, and the creep behavior, was investigated. The observations of microstructures through thescanning electron microscope (SEM) showed that in the incompatibilized blends, the interfacial adhesion of the phases was very weak. In contrast, in compatibilized samples, the broken surface of starch was observed confirming the enhanced interfacial tension. Additionally, the increase in the starch content led to the rise in the relaxation times. The creep test results revealed that with the increment of starch content, the creep of the blends increased. The compatibilizer improved the creep recovery of the blends. Moreover, by addition of the compatibilizer, the values of the creep parameters including η, E₁, E_2, and τ_R obtained from the standard linear solid model (SLS), was higher than those for the incompatibilized blends. The addition of POE-MA compatibilizer can improve the properties of POE/starch blends, while keeping their biocompatibility. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48877.     

Effect of inulin formulation on the microstructure and viscoelastic properties of low‐fat mayonnaise containing modified starch

Combinations of three types of inulin differing in the degree of polymerization, that is, short, medium, and long chained (0–10%), and modified starch (0–3%) with different composition ratios were prepared according to the D‐optimal design of experiments. The microstructural and rheological characteristics of the prepared samples were analyzed to study the effect of the inulin composition on the low‐fat mayonnaise. Rheological characterizations, including oscillatory frequency sweep tests, transient creep, and stress relaxation analysis, were carried out on the samples. An optical microscope was used to observe the microstructure. According to the results, the effects of all types of inulin were precarious in the presence of starch (≥1.5%). In fact, a relationship was found between the inulin type and concentration and also the starch content in all of the prepared samples; with increasing starch content (≥1.5%), inulin chain length, and concentration of long‐chain inulin (≥5%), the elastic properties of the emulsion were improved and showed a higher resistivity against deformation. Furthermore, a more packed structure with a larger average particle diameter and dominant monodispersity were observed under such conditions. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 801‐809, 2013     

Application of time–stress superposition to viscoelastic behavior of polyamide 6,6 fiber and its “true” elastic modulus

The viscoelastic behavior of semi‐crystalline polyamide 6,6 fiber is exploited in viscoelastically prestressed polymeric matrix composites. To understand better the underlying prestress mechanisms, strain–time performance of the fiber material is investigated in this work, under high creep stress values (330–665 MPa). A latch‐based Weibull model enables prediction of the “true” elastic modulus through instantaneous deformation from the creep‐recovery data, giving 4.6 ± 0.4 GPa. The fiber shows approximate linear viscoelastic characteristics, so that the time–stress superposition principle (TSSP) can be implemented, with a linear relationship between the stress shift factor and applied stress. The resulting master creep curve enables creep behavior at 330 MPa to be predicted over a large timescale, thus creep at 590 MPa for 24 h would be equivalent to a 330 MPa creep stress for ～5200 years. Similarly, the TSSP is applied to the resulting recovery data, to obtain a master recovery curve. This is equivalent to load removal in the master creep curve, in which the yarns would have been subjected to 330 MPa creep stress for ～4.56 × 10⁷ h. Since our work involves high stress values, the findings may be of interest to those involved with long‐term load‐bearing applications using polyamide materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44971.     

Effect of styrene–isoprene–styrene,styrene–butadiene–styrene,and styrene–butadiene–rubber on the mechanical,thermal, rheological,and morphological properties of polypropylene/polystyrene blends

The mechanical, thermal, rheological, and morphological properties of polypropylene (PP)/polystyrene (PS) blends compatibilized with styrene–isoprene–styrene (SIS), styrene–butadiene–styrene (SBS), and styrene–butadiene–rubber (SBR) were studied. The incompatible PP and PS phases were effectively dispersed by the addition of SIS, SBS, and SBR as compatibilizers. The PP/PS blends were mechanically evaluated in terms of the impact strength, ductility, and tensile yield stress to determine the influence of the compatibilizers on the performance properties of these materials. SIS‐ and SBS‐compatibilized blends showed significantly improved impact strength and ductility in comparison with SBR‐compatibilized blends over the entire range of compatibilizer concentrations. Differential scanning calorimetry indicated compatibility between the components upon the addition of SIS, SBS, and SBR by the appearance of shifts in the melt peak of PP toward the melting range of PS. The melt viscosity and storage modulus of the blends depended on the composition, type, and amount of compatibilizer. Scanning electron microscopy images confirmed the compatibility between the PP and PS components in the presence of SIS, SBS, and SBR by showing finer phase domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 266–277, 2003