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The objective of this paper is investigating the effect of different localizations of titanium dioxide (Ti[O.sub.2]) and hexagonal boron nitride (hBN) nanoparticles in the poly(lactic acid) (PLA)/poly([epsilon]-caprolactone) (PCL) blends on the ultraviolet (UV) blocking, infrared reflection (NIR), and thermal conductivity of the nanocomposites for the fabrication of bionanocomposites with high performance. Transmission electron microscopy images demonstrated that the different mixing sequences induced different nanoparticle localization in the immiscible PCL/PLA blend. These different localizations yielded differences in the properties of the hybrid quaternary nanocomposite. When the nanoparticles had different localizations, Ti[O.sub.2] at the interface and hBN in the PCL phase, the thermal conductivity was 0.86 W[m.sup.-1] [K.sup.-1], 100% of UV radiation ([lambda] = 300 nm) was blocked and 74% of NIR radiation was reflected. This nanocomposite has a strong potential for application as a multifunctional biodegradable film for agriculture, capable of absorbing UV radiation, reflecting NIR radiation, and conducting thermal energy. KEYWORDS bionanocomposites, infrared reflection, thermal conductivity, ultraviolet absorption, 1 | INTRODUCTION Studies have shown that the use of polymeric films with a high near-infrared reflection (NIR) reflection and a high ultraviolet (UV) filtration or UV blocking, in applications [...]

In this study, the effects of processing conditions through different mixing sequences were used to analyze the factors, which could influence the hybrid filler selective localization in an immiscible polymer blend and how localization can influence the rheological and thermal properties. Different selective localizations were observed depending on the mixing sequence used when the hybrid filler was added. Notably, nanoparticles can interact with each other, which favor a synergy between them and alters, besides the localization, the dispersion state, or can interact with one polymer phase, and also alter the nanoparticles' selective localization. An improvement in rheological properties was observed in the hybrid nanocomposite in which there was interaction between the nanoparticles, favoring the hexagonal boron nitride exfoliation. On the other hand, for the storage modulus and degree of crystallinity, the sharpest increase occurred in the hybrid nanocomposite in which the nanoparticles could interact preferably with one polymer phase. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48711. [ABSTRACT FROM AUTHOR]

Montmorillonite clay (MMT) was modified with polyaniline (Pani) and used to produce nanocomposites in a polystyrene (PS) matrix. MMT/Pani particles were evaluated by Infrared Spectroscopy (FT‐IR), where groups of both MMT and Pani were found; and by XRD, where an increase in the interlamellar distance was detected, changes on the resistive electrical behavior of MMT to a diffusive one for MMT/Pani were identified by Electrochemical Impedance Spectroscopy (EIS). Nanocomposites of PS with MMT‐Pani were produced by melt intercalation in the proportions of 1%, 3%, 5%, and 10%. They were characterized by Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), and EIS. Main results showed a decrease in the glass transition temperature and in the onset temperature according to the amount of MMT‐Pani. Analyses by EIS demonstrated a capacitive behavior (polarization) for nanocomposites containing smaller amounts of MMT‐Pani and diffusive behavior for the largest proportions, which were explained by a model of electronic diffusion in the Pani polymeric chain due to the chain intercalation observed by TEM in samples with higher concentration of MMT‐Pani. Therefore, the results suggest that the addition of MMT‐Pani alters some properties of the polystyrene matrix, changing its degradation and transition temperature, and its electrical behavior. POLYM. COMPOS., 40:37–45, 2019. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

ABSTRACT In this work, the effect of TiO2 addition over morphological and ultraviolet (UV) blocking properties of poly(lactic acid) (PLA) and poly(ɛ-caprolactone) (PCL) blends was investigated. The micrographs showed a partially co-continuous structure in the PLA/PCL blend with 42/58 (wt %/wt %) and the TiO2 nanoparticles addition leads to a structural phase inversion, i.e., continuous PCL and partially continuous PLA with a dispersed portion. TiO2 nanoparticles were observed to be preferably localized at the interface of the two phases due to kinetic effects (large difference between the melting temperatures) and nanoparticle geometry (low aspect ratios). An adhesion improvement between the phases and morphological stability were observed with the addition of TiO2 nanoparticles. This behavior indicates that the nanoparticles can act as compatibilizers due to their localization at the interface between the two phases. The UV light absorption and transmission percolation threshold occurred with 1.5% TiO2 in the 42PLA/52PCL blend. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45813. [ABSTRACT FROM AUTHOR]

Poly(lactic acid)'s (PLA) mechanical and barrier properties depend on the solid‐state morphology and crystallinity. To overcome those limitations, plasticizers and nanoparticles are added. Common plasticizers for PLA, such as poly(ethyleneglycol) (PEG) and dibutyl sebacate (DBS), as well as graphene, were used in this work. Therefore, the combined effects of such additions in PLA's mechanical, thermal, and electrical properties were evaluated. The relation between graphene concentration and dispersion was different when DBS or PEG was used. The best dispersion was observed with the lowest (0.25% wt) graphene concentration in the composites with DBS. When PEG was used as plasticizer, the highest (0.5% wt) concentrations of graphene resulted in good dispersion. The best Young's modulus results were observed in the nanocomposites with better graphene dispersion, but the presence of graphene agglomerates seemed to lower the charge transfer resistance, probably because they prevent the plasticizers' diffusion to the surface and the formation of a second phase. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46745. [ABSTRACT FROM AUTHOR]