Mechanical Strength Of Blends Research Articles

Preparation and Properties of PA10T/PPO Blends Compatibilized with SEBS-g-MAH.

Plant-derived PA10T is regarded as one of the most promising semi-aromatic polyamides; however, shortcomings, including low dimensional accuracy, high moisture absorption, and relatively high dielectric constant and loss, have impeded its extensive utilization. Polymer blending is a versatile and cost-effective method to fabricate new polymeric materials with excellent comprehensive performance. In this study, various ratios of PA10T/PPO blends were fabricated via melt blending with the addition of a SEBS-g-MAH compatibilizer. Molau test and scanning electron microscopy (SEM) were employed to study the influence of SEBS-g-MAH on the compatibility of PA10T and PPO. These studies indicated that SEBS-g-MAH effectively refines the domain size of the dispersed PPO phase and improves the dispersion stability of PPO particles within a hexafluoroisopropanol solvent. This result was attributed to the in situ formation of the SEBS-g-PA10T copolymer, which serves as a compatibilizer. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) results showed that the melting-crystallization behavior and thermal stability of blends closely resembled that of pure PA10T. Dynamic mechanical analysis (DMA) revealed that as the PPO content increased, there was a decrease in the glass transition temperature and storage modulus of PA10T. The water absorption rate, injection molding shrinkage, dielectric properties, and mechanical strength of blends were also systematically investigated. As the PPO content increased from 10% to 40%, the dielectric loss at 2.5 GHz decreased significantly from 0.00866 to 0.00572, while the notched Izod impact strength increased from 7.9 kJ/m2 to 13.7 kJ/m2.

Study on phenolphthalein poly(ether sulfone)‐modified cyanate ester resin and epoxy resin blends

In this work, the phenolphthalein poly(ether sulfone) (PES‐C)‐modified cyanate ester (CE) and epoxy (EP) blends were prepared. This work mainly discusses the curing behaviors, fracture toughness, dynamic mechanical properties, and thermal and mechanical properties of the blends. The Fourier transform infrared and differential scanning calorimetric analyses are used to confirm the curing behaviors, demonstrating that the main reaction pathways are not varied with the addition of PES‐C, but the reaction rate could be evidently accelerated. The fracture morphologies of the blends are observed by Scanning electron microscope (SEM) and the fracture causes of the failed surface are also analyzed. With the addition of PES‐C, the modified blends display higher fracture toughness (KIc) and impact strength when compared with neat CE. Domain sizes of the blends first increase then decrease with the addition of PES‐C. The results of dynamic mechanical analysis and thermogravimetric analysis show that the Tg, storage modulus, and thermal stability of the crosslink network slightly decreases with the addition of PES‐C. The mechanical strength of blends with the addition of PES‐C is far better than that of the blends without PES‐C both at ambient temperature and elevated temperature. POLYM. ENG. SCI., 55:2591–2602, 2015. © 2015 Society of Plastics Engineers

In vitro degradation of poly(l-lactide)/poly(ε-caprolactone) blend reinforced with MWCNTs

The physical and mechanical properties of poly(l-lactide)/poly(e-caprolactone) (PLLA/PCL) blends reinforced with multiwalled carbon nanotubes (MWCNTs) before and after in vitro degradation were investigated. Because of brittleness, PLLA needs to be plasticized by PCL as a soft polymer. The MWCNTs are used to balance the stiffness and the flexibility of PLLA/PCL blends. The results showed that with incremental increase in concentration of MWCNTs in composites, the agglomerate points of MWCNTs were increased. The physical and mechanical properties of prepared PLLA/PCL blends and MWCNT/PLLA/PCL nanocomposites were characterized. The X-ray diffraction analysis of the prepared blends and composites showed that MWCNTs, as heterogeneous nucleation points, increased the lamella size and therefore the crystallinity of PLLA/PCL. The mechanical strength of blends was decreased with incremental increase in PCL weight ratio. The mechanical behavior of composites showed large strain after yielding and high elastic strain characteristics. The tensile tests results showed that the tensile modulus and tensile strength are significantly increased with increasing the concentration of MWCNTs in composites, while, the elongation-at-break was decreased. The in vitro degradation rate of polymer blends in phosphate buffer solution (PBS) increased with higher weight ratio of PCL in the blend. The in vitro degradation rate of nanocomposites in PBS increased about 65% when the concentration of MWCNTs increased up to 3% (by weight). The results showed that the degradation kinetics of nanocomposites for scaffolds can be engineered by varying the contents of MWCNTs.

Mechanical strength of blends of Eudragit RL 100 and poly(methyl methacrylate)

Plaques of blends of Eurdragit RL 100 and poly(methyl methacrylate) (PMMA) with different weight percentage ratios were obtained by compression moulding at 150°C. The mechanical strength of these blends was studied by a microindentation technique. The results show a decrease in brittleness and increase in hardness, toughness and yield strength by addition of PMMA to Eudragit.