Polycaprolactone (PCL) is one of the most used synthetic polymers for medical applications due to its biocompatibility and slow biodegradation character. Combining the inherent properties of the PCL matrix with the characteristic of nanofibrous particles, result into promising materials that can be suitable for different applications, including the biomedical applications. The advantages of nanofibrous structures include large surface area, a small diameter of pores and a high porosity, which make them of great interest in different applications. Electrospinning, as technique, has been heavily used for the preparation of nano- and micro-sized fibers. This review discusses the different methods for the electrospinning of PCL and its composites for advanced applications. Furthermore, the steady state conditions as well as the effect of the electrospinning parameters on the resultant morphology of the electrospun fiber are also reported.

In recent times, the field of biopolymer (BP) blends has been the focus of intensive fundamental and applied researches. Such BP combinations possess unique properties that are different from those of the individual components. However, most polyester polymers are thermodynamically immiscible because of their poor interactions. In the past, a third component, known as a well‐defined diblock or triblock copolymer, whose chemical structure is identical to that of the main components, was usually used as a compatibilizer in order to emulsify the interfacial phase, decreasing the interfacial tension and refining the phase size. Currently, nanofillers are used to improve the phase morphologies of immiscible BP blends. The main advantage of using nanofillers, when compared to copolymers, is that the former can simultaneous act as nano‐reinforcements and compatibilizers. In this review, the addition of nanofillers as the third component in the BP blend systems are reported in relation to their morphologies, barrier properties, shape memory, thermal, and mechanical properties. The effects of selectively localized nanofillers on the properties of the BP blends are also explored, with the aim of establishing the relationships between the localization of the fillers and the overall properties of the BP blends. Furthermore, the effect of the processing techniques on the localization of the nanofillers/BP blend is also reported. The review article discusses recent progress from 2014 up to 2019 on filler localization of BP blend nanocomposites.

This study covers the preparation and the characterization of b-nucleated impact polypropylene copolymer (NA-IPC). Calcium stearate (CaSt), as well as pimelic (Pim) and adipic (Adi) acids, were doped into IPC as mono-or bicomponent nucleating agents (NAs) at varying mass ratios. Possible chemical interactions between the NAs and with IPC, as well as the effect of the NAs on the crystallization behavior and nonisothermal crystallization kinetics, were investigated. DSC and XRD results revealed that IPC nucleated with Pim and Pim-CaSt nucleants induced up to 90% b-crystals, whereas Adi and Adi-CaSt formed only about 17% b-crystals. This was associated with the strong nucleation efficiency of Pim. The nonisothermal crystallization kinetics showed that the crystallization of IPC and NA-IPC followed a three-dimensional growth with athermal nucleation mechanism. FTIR showed that none of the NAs chemically reacted with IPC, and the chemical structure of the polymer was thus intact during the treatment. V C 2013Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39923.

Abstract:The effect of a -nucleating agent ( -NA) on the properties and structure of a commercial impact polypropylene copolymer (IPC) was investigated. The effect of selected -NAs on the impact resistance, stress and strain behaviour of the IPC is reported. In addition, the IPC was fractionated according to crystallinity by preparative temperature rising elution fractionation. Fractions with varying chemical composition and crystallinity were treated with a two-component -NA to investigate the effect of the -NA on the various fractions. The results indicate that the efficacy of the -NA is dependent on the chemical composition of the polymer that crystallises, more specifically on the sequence length of crystallisable propylene units. The effect of the addition of -NAs on the overall morphology of the IPC was also investigated, and in particular the size and distribution of the rubbery particles in these complex reactor blends were probed.

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