Crystallization behavior of polymer/montmorillonite nanocomposites. Part II. Intercalated poly(ε-caprolactone)/montmorillonite nanocomposites

Effect of Cu Nanoparticles on the Properties of PP-g-PHMG/PE Monofilament and Its Antifouling Application

The modified polyethylene monofilament was prepared by melt blending and spinning using polyethylene (PE), polypropylene-grafted poly(hexamethylene guanidine) (PP-g-PHMG), and Cu nanoparticles (CuNPs). The effect of CuNP content on the structure, mechanical properties, and antimicrobial properties of the monofilaments was studied. In addition, the antifouling property of fishing nets using the modified polyethylene monofilaments was evaluated. The results showed that CuNPs were dispersed homogeneously in the monofilament matrix as microaggregates. The initial increase in the tensile strength of monofilament was attributed to the mechanical restraint, whereas a decrease in the tensile properties at 1.0 wt% CuNP content was due to the predominant effect of a decrease in the total crystallinity. A bacteriostatic test showed that the monofilament had an obvious inhibitory effect on Staphylococcus aureus. Furthermore, coupon test results showed that PP-g-PHMG/PE/CuNP nanocomposite netting had lower weight gain than PP-g-PHMG/PE netting (23.6% reduction) because of the combined antibacterial effect of both PHMG and CuNP. Therefore, PP-g-PHMG/PE/CuNP monofilament has the potential to produce green and efficient antifouling fishing nets.

Cu Nanoparticle-Modified High-Density Polyethylene Monofilament and Its Antifouling Performance on Fishing Netting

Cu nanoparticles (CuNPs) were modified by organic surfactant, then CuNP-modified high-density polyethylene (CuNP/HDPE) monofilaments were prepared by melt spinning. The effect of CuNP content on the morphology and properties of nanocomposite monofilaments was investigated. FT-IR and dynamic light scattering proved the successful surface modification for CuNP. Scanning electron microscope was used to observe the dispersed behavior of the CuNP. When the CuNP content was less than 1.0 wt%, the CuNPs were well dispersed in these nanocomposite monofilaments, and the increase of crystallization rate, the breaking strength, and knot strength were observed by differential scanning calorimeter and tensile test. Therefore, nanocomposite monofilaments showed comparable properties at low CuNP contents. With increasing CuNP content, the width of tanδ peak and △Ea for α-relaxation from dynamic mechanical analysis were increased, indicating more amorphous components near the crystalline regions. In addition, burst release of Cu ions in seawater was observed. The coupon tests demonstrated that CuNPs could significantly improve antibiofouling performance of CuNP/HDPE fishing netting. CuNP/HDPE fishing netting have a strong potential for using in marine antifouling mitigation.

Morphology and thermal properties of clay based biocomposites

Carboxymethylcellulose/poly(ethylene glycol) (CMC/PEG) blend and CMC/PEG/montmorillonite (MMT) nanocomposites were produced by the solvent casting method. The clay, a sodium MMT, was incorporated in the polymer matrix at low weight loadings (from 1 wt% to 7 wt%). The MMT dispersion in the matrix was evaluated by X-ray diffraction, which revealed an intercalated structure of the nanocomposites. Different levels of intercalation have been detected. The changes in morphology caused by the addition of layered silicate on CMC/PEG blend were investigated by scanning electron microscopy (SEM). The SEM images of CMC/PEG blend containing 5% of MMT displayed more homogenous morphology than CMC/PEG blend. The compatibilizing performance of the filler was investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. The effect of the introduction of the clay on the crystallization temperature, melting temperature and crystallization degree of CMC/PEG revealed that clay behaved as a nucleating agent and enhanced the crystallization rate of PEG. Furthermore, it was demonstrated that the addition of a small percentage of montmorillonite (1%) was enough to improve the thermal stability of the nanocomposites.

Preparation and characterization of interface-modified PLA/starch/PCL ternary blends using PLLA/triclosan antibacterial nanoparticles for medical applications

In this study, the antibacterial, interface-modified ternary blends based on polylactic acid/starch/polycaprolactone were prepared for medical applications.

Confined crystallization of poly(butylene succinate) intercalated into organoclays: role of surfactant polarity

Understanding isothermal crystallization kinetics and crystalline morphology of PBS in the presence of a nanoclay is crucial to reveal the relationship between properties, morphology, as well as the processing of PBS/clay nanocomposites.

Nanoparticle-induced controlled biodegradation and its mechanism in poly(epsilon-caprolactone)

Poly(epsilon-caprolactone) (PCL)/layered silicate nanocomposites have been prepared via solution route. Two different organically modified nanoclays were used to compare the variation in properties based on organic modifications. The nanostructures, as observed from wide-angle X-ray diffraction and transmission electron microscopy, indicate intercalated and partially exfoliated hybrids depending on the nature of organic modification in nanoclay. The nanohybrids exhibit significant improvement in thermal and mechanical properties of the matrix as compared to neat polymer. The nanoclays act as nucleating agent for the crystallization of PCL. The biodegradability of pure PCL and its nanocomposites have been studied under controlled conditions in enzyme, pure microorganism (fungi), compost, Ganges water, and alkaline buffer solution. The rate of biodegradation of PCL has enhanced dramatically in nanohybrids and depends strongly on the media used. Scanning confocal, electron, and atomic force microscopes have used to demarcate the nature of biodegradation of pristine PCL and its nanocomposites. The change in biodegradation is rationalized in terms of the crystallization behavior and organic modification in nanoclays of the nanohybrids vis-a-vis the neat polymer. The extent of compatibility was measured quantitatively through the interaction parameter for two different nanoclays to compare and establish the reason for variation in their properties in nanohybrids. A biodegradation mechanism has been revealed for PCL and its nanocomposites through enzyme activity in varying pH environment.

Microscopic morphology of chlorinated polyethylene-based nanocomposites synthesized from poly(epsilon-caprolactone)/clay masterbatches

Chlorinated polyethylene (CPE) nanocomposites were synthesized by melt blending clay-rich/poly(epsilon-caprolactone) (PCL) masterbatches to CPE matrices. The masterbatches were prepared following two synthetic routes: either PCL is melt-blended to the clay or it is grafted to the clay platelets by in situ polymerization. The microscopic morphology of the nanocomposites was characterized by X-ray diffraction, atomic force microscopy, transmission electron microscopy, and modulated temperature differential scanning calorimetry. When using free PCL, intercalated composites are formed, with clay aggregates that can have micrometric dimensions and a morphology similar to that of the talc particles used as fillers in commercial CPE. PCL crystallizes as long lamellae dispersed in the polymer matrix. When using grafted PCL, the nanocomposite is intercalated/exfoliated, and the clay stacks are small and homogeneously dispersed. PCL crystallizes as lamellae and smaller crystals, which are localized along the clay layers. Thanks to the grafting of PCL to the clay platelets, these crystalline domains are thought to form a network with the clay sheets, which is responsible for the large improvement of the mechanical properties of these materials.