Enhanced High-Performance iPP/TPU/MWCNT Nanocomposite for Electromagnetic Interference Shielding.

The rapid development of electronic communication technology has led to an undeniable issue of electromagnetic pollution, prompting widespread attention from researchers to the study of electromagnetic shielding materials. Herein, a simple and feasible method of melt blending was applied to prepare iPP/TPU/MWCNT nanocomposites with excellent electromagnetic shielding performance. The addition of maleic anhydride-grafted polypropylene (PP-g-MAH) effectively improved the interface compatibility of iPP and TPU. A double continuous structure within the matrix was achieved by controlling the iPP/TPU ratio at 4:6, while the incorporation of multi-walled carbon nanotubes endowed the composites with improved electromagnetic shielding properties. Furthermore, by regulating the addition sequence of raw materials during the melt-blending process, a selective distribution of carbon nanotubes in the TPU matrix was achieved, thereby constructing interconnected conductive networks within the composites, significantly enhancing the electromagnetic shielding performance of iPP/TPU/MWCNTs, which achieved a maximum EMI shielding efficiency of 37.8 dB at an iPP/TPU ratio of 4:6 and an MWCNT concentration of 10 wt.%.

In Situ Formation of Compound Eye-like SAN-OSB Composite Microspheres by Melt-Blending Method: Enhancing Multiple-Scattering Effect.

The preparation of novel structures of light-diffusing particles is currently a research focus in the field of light-diffusing materials. This study, conducted by the common melt-blending process, controlled thermodynamic and kinetic factors to distribute smaller-sized organic silica bead (OSB) particles at the interface between a polycarbonate (PC) matrix and spherical island-phase styrene-acrylonitrile copolymer (SAN) for the in situ formation of compound eye-like microspheres with SAN as "large eyes" and OSBs as "small eyes". Through the multiple-scattering effects of these compound eye-like microspheres, these light-diffusing materials significantly improved the haze, scattering range, and light-shielding capabilities while maintaining high transmittance. Specifically, the PC/SAN-OSB light-scattering materials achieved a haze of 100% with an OSB content of only 0.17%, maintaining a transmittance of 88%. Compared with the PC/OSB system with the same level of haze, the addition of OSB was reduced by 88%. Therefore, this study achieved exceptionally effective light-diffusing materials through a simple, environmentally friendly, and low-cost preparation method, suitable for the scalable production of light-diffusing materials in new display and lighting fields.

Preparation of Esterified Starches with Different Amylose Content and Their Blending with Polybutylene Succinate.

Three types of starch with different amylose content were esterified and blended with polybutylene succinate (PBS) to obtain esterified manioc starch/PBS (EMS/PBS), esterified corn starch/PBS (ECS/PBS), and esterified waxy corn starch/PBS (EWS/PBS) composites. The EMS/PBS and ECS/PBS composites with high amylose content displayed typical V-type crystal structures. The original crystals of EWS, which had low amylose content, were disrupted during the esterification process. EWS exhibited the strongest interaction with PBS and the most favorable interface compatibility. The pyrolysis temperature was in order of EMS/PBS < ECS/PBS < EWS/PBS. The elongation at break of the three blends was higher than that of pure PBS. The esterification and plasticization of the EWS/PBS composite were the most comprehensive. The EWS/PBS composite showed the lowest storage modulus (G') and complex viscosity (η*). The interfacial bonding force of the composite materials increased with more amylopectin, decreasing intermolecular forces and destroying crystal structures, which decreased G' and η* and increased toughness. The EWS/PBS composite, with the least amylose content, had the best hydrophobicity and degradation performance.

Biodegradable Nanocomposites Based on Blends of Poly(Butylene Adipate-Co-Terephthalate) (PBAT) and Thermoplastic Starch Filled with Montmorillonite (MMT): Physico-Mechanical Properties.

Poly(butylene adipate-co-terephthalate) (PBAT) is widely used for production of biodegradable films due to its high elongation, excellent flexibility, and good processability properties. An effective way to develop more accessible PBAT-based bioplastics for wide application in packaging is blending of PBAT with thermoplastic starch (TPS) since PBAT is costly with prices approximately double or even triple the prices of traditional plastics like polyethylene. This study is focused on investigating the influence of TPS/PBAT blend ratio and montmorillonite (MMT) content on the physical and mechanical properties and molecular mobility of TPS-MMT/PBAT nanocomposites. Obtained TPS-MMT/PBAT nanocomposites through the melt blending process were characterized using tensile testing, dynamic mechanical thermal analysis (DMTA), and X-ray diffraction (XRD), as well as solid-state 1H and 13C NMR spectroscopy. Mechanical properties demonstrated that the addition of TPS to PBAT leads to a substantial decrease in the tensile strength as well as in the elongation at break, while Young's modulus is rising substantially, while the effect of the MMT addition is almost negligible on the tensile stress of the blends. DMTA results confirmed the formation of TPS domains in the PBAT matrix. With increasing TPS content, mobility of starch-rich regions of TPS domains slightly increases. However, molecular mobility in glycerol-rich regions of TPS domains in the blends was slightly restricted. Moreover, the data obtained from 13C CP/MAS NMR spectra indicated that the presence of TPS in the sample decreases the mobility of the PBAT chains, mainly those located at the TPS/PBAT interfaces.

Hybrid Green Materials Obtained by PCL Melt Blending with Diatomaceous Earth.

In this work, diatomaceous earth (Diat) was explored as filler for polycaprolactone (PCL) to obtain composite green materials with promising viscoelastic and thermal properties. The composites were prepared by blending variable Diat amounts (5, 15 and 50 wt%) with a molten PCL matrix. The viscoelastic characteristics of PCL/Diat hybrids were studied by Dynamic Mechanical Analysis (DMA) under an oscillatory regime, while the thermal properties were determined by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). We detected that the presence of Diat enhances the energy storage capacity of PCL for temperatures lower than the polymer melting point. Both DMA and DSC data revealed that the PCL melting temperature is slightly affected by the Diat addition, while the TGA results showed that the thermal stability of the polymer can be significantly improved by mixing PCL with diatomaceous earth. Moreover, we observed that the dispersion of Diat into the matrix favors the crystallization process of PCL. Interestingly, the improvements of PCL properties (elasticity, thermal stability, and crystallinity) are proportional to the Diat concentration of the composites. These findings reflect the interfacial compatibility between PCL and diatomaceous earth. In conclusion, this study highlights that the preparation of PCL/Diat hybrids by melt blending is suitable for the development of composite materials for technological applications, including the remediation of air pollutants within museum environments.

A Polymer Nanocomposite with Strong Full-Spectrum Solar Absorption and Infrared Emission for All-Day Thermal Energy Management and Conversion.

Realizing efficient energy utilization from the heat source of the sun and the cold source of outer space is of great significance for addressing the global energy and environmental crisis. Materials with ideal full-spectrum solar absorption and infrared emission are highly desirable for adapting to the continuous weather dynamic throughout the day, nonetheless, their development remains challenging. Here, a polymer nanocomposite with full-spectrum strong solar (280-2500 nm) absorption ranging from 88.8% to 94.8% with an average value of 93.2% and full-spectrum high infrared (8-13 µm) emission ranging from 81.3% to 90.0% with an average value of 84.2%, is reported by melt-processing polypropylene and uniformly dispersed low-loading MXene nanosheets (1.9 vol%). The nanocomposite can achieve daytime photothermal enhancement of ≈50 °C and nighttime radiative cooling of 8 °C. The temperature difference throughout the day ensures all-day uninterrupted thermoelectric generation, yielding a power density output of 1.5 W m-2 (daytime) and 7.9 mW m-2 (nighttime) in real outdoor environment without any additional energy consumption. This work provides an impressive polymer nanocomposite with ideal full-spectrum solar absorption and infrared emission for all-day uninterrupted thermal energy management and conversion.

Crystallinity, Rheology, and Mechanical Properties of Low-/High-Molecular-Weight PLA Blended Systems.

As semi-crystalline polyester (lactic acid) (PLA) is combined with other reinforcing materials, challenges such as phase separation, environmental pollution, and manufacturing difficulties could hinder the benefits of PLA, including complete biodegradability and strong mechanical properties. In the present investigation, melt blending is utilized to establish a mixture of low- and high-molecular-weight polylactic acids (LPLA and HPLA). The crystallinity, rheology, and mechanical properties of the combination were analyzed using rotational rheometry, differential scanning calorimetry, X-ray diffraction, polarized optical microscopy, scanning electron microscopy, and universal testing equipment. The results demonstrate compatibility between LPLA and HPLA. Moreover, an increase in LPLA concentration leads to a decrease in the crystallization rate, spherulite size, fractional crystallinity, and XRD peak intensity during isothermal crystallization. LPLA acts as a diluent during isothermal crystallization, whereas HPLA functions as a nucleating agent in the non-isothermal crystallization process, promoting the growth of LPLA crystals and leading to co-crystallization. The blended system with a 5% LPLA mass fraction exhibits the highest tensile strength and enhances rheological characteristics. By effectively leveraging the relationship between various molecular weights of PLA's mechanical, rheological, and crystallization behavior, this scrutiny improves the physical and mechanical characteristics of the material, opening up new opportunities.