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Nanoparticles of zinc oxide (ZnO), polyhedral oligomeric silsesquioxane (POSS), and their hybrids were added to polylactic acid (PLA) using solution casting process at different weight percentages of the nanoparticles (1, 3, and 5 wt%) to form developed nanocomposites for food packaging applications. According to FTIR and XRD studies, both nanoparticles displayed fair chemical interactions with the PLA matrix. Furthermore, morphological investigations (SEM‐EDS) revealed that POSS, ZnO, and their hybrids were uniformly dispersed into the matrix despite some microaggregations at 5 wt% of nanoparticles, especially for those containing POSS. Moreover, adding 1 wt% of POSS to PLA increased its tensile strength and modulus by 20% and 149%, respectively, while decreasing the elongation‐at‐break by 54%. In addition, the tensile strength, tensile modulus, and elongation‐at‐break of PLA all increased by 7.5%, 28.7%, and 162%, respectively, with the addition of 1 wt% ZnO. Contact angle and surface free energy experiments demonstrated that after incorporating ZnO and POSS into the PLA matrix, the hydrophobicity of the samples increased, and POSS nanoparticles could minimize bacterial adherence effectively. In addition to the antibacterial properties of ZnO and POSS nanoparticles, increasing the concentration of hybrid nanoparticles up to 5 wt% expanded the bacteria's inhibitory zone, particularly in the case of Gram‐positive bacteria (Staphylococcus aureus). Finally, the hybrid nanocomposites exhibited both balanced mechanical characteristics and promising antibacterial activity compared with those with ZnO and POSS alone. [ABSTRACT FROM AUTHOR]

An environmentally friendly free-carrier technique was used to prepare poly propylene/poly(trimethylene terephthalate) (PP/PTT) blend fibers. As PTT loading increased, its average diameter enhanced, and its distribution narrowed. In addition, the results of mechanical properties demonstrated that incorporating PTT into the PP matrix led to a decrease in tenacity and elongation-at-break. The more the PTT content, the less the tenacity and the elongation-at-break. Moreover, the crystallinity of PP enhanced by about 12% when 20 wt.% PTT was incorporated while melting and crystallization temperatures did not change remarkably. The molten blends indicated almost a Newtonian behavior. On the other hand, the storage modulus enhanced almost linearly in the frequency range of 1–1000 1/sec for all samples. Also, approximately 60% improvement in dyeability and 10% progress in resiliency behavior were observed. The dye uptake ability of samples was improved with the addition of PTT. In addition, the washing and light fastness of the blends were admissible for textile fibers. Generally, blends with PTT content less than 20 wt.% exhibited better physical and mechanical properties, especially resiliency behavior. Therefore, PP/PTT blend fibers are promising candidates for use in textiles in the coming years. [ABSTRACT FROM AUTHOR]

Four-dimensional (4 D) printing is a novel emerging technology, which can be defined as the ability of 3 D printed materials to change their form and functions. The term 'time' is added to 3 D printing as the fourth dimension, in which materials can respond to a stimulus after finishing the manufacturing process. 4 D printing provides more versatility in terms of size, shape, and structure after printing the construct. Complex material programmability, multi-material printing, and precise structure design are the essential requirements of 4 D printing systems. The utilization of stimuli-responsive polymers has increasingly taken the place of cell traction force-dependent methods and manual folding, offering a more advanced technique to affect a construct's adjusted shape transformation. The present review highlights the concept of 4 D printing and the responsive bioinks used in 4 D printing, such as water-responsive, pH-responsive, thermo-responsive, and light-responsive materials used in tissue regeneration. Cell traction force methods are described as well. Finally, this paper aims to introduce the limitations and future trends of 4 D printing in biomedical applications based on selected key references from the last decade. [ABSTRACT FROM AUTHOR]

An attempt was made to explore the effects of the interchange reactions on the viscoelastic behavior of binary blends based on poly(ethylene terephthalate) (PET)/poly(ethylene naphthalate) (PEN) and their nanocomposites. It was seen that with an increase in the number of extrusion runs and mixing temperature, the extent of reaction (X) and degree of randomness (RD) both increased, whereas the average sequence block lengths values were decreased. On the contrary, the blend composition did not play a significant role on X and RD values. Addition of nanoclay inhibited the transreactions in PET/PEN blends. The absence of crystallization peaks implied that the crystalline structure was destroyed as a result of blending and an amorphous system was created possibly due to the transreactions simultaneously with the formation of random copolymers inhibiting the crystallization process. The rheological investigations showed that the addition of PEN into the PEN/PET blends enhanced the storage modulus, loss modulus, and complex viscosity. The viscosity upswing observed at low-frequency region in the case of nanocomposite systems evidently confirmed the occurrence of transreactions. Nonetheless, a significant increment in the viscoelastic properties was perceived in the presence of nanoclay corroborating the proper nanoclay distribution throughout the PET/PEN blend system. POLYM. ENG. SCI., 53:2556-2567, 2013. © 2013 Society of Plastics Engineers, INTRODUCTION The aromatic polyesters of unique properties are of substantial importance due to the desirable performance. They are well-suited materials for various applications because of their low permeability to gases, [...]

Effect of concurrent inclusion of two type fillers, i.e. OMMT and NOR, on rheological, morphological, thermal and flame retardant properties of the PP/PEVA blends has been studied. The co-continuous morphology became finer with OMMT, NOR and OMMT/NOR inclusion. The result of rheological study revealed that the polymer blend and the NOR loaded composite possess liquid-like, whereas the OMMT composites represent solid-like behavior. Moreover, in OMMT loaded composite, a G' and G" crossover in low frequency range appeared due to formation of network-like structure between OMMT layers. Thermogravimetric analysis corroborated the concurrent inclusion of OMMT and NOR in nitrogen atmosphere decreases To by 2%, increases the Tmax1 by 0.9% and increases Tmax2 by 2% comparing the blended composition. The results of microscale combustion calorimetry showed that concurrent incorporation of OMMT and NOR decreases the peak heat release rate and total heat release by 32% and 4% comparing the polymer blend, respectively. [ABSTRACT FROM AUTHOR]