Dynamic rheological behavior and mechanical properties and of PVC/ASA blends

Preparation of core/shell organic–inorganic hybrid polymer nanoparticles and their application to toughening poly(methyl methacrylate)

On account of the utility of poly(methyl methacrylate) (PMMA) as a glass substitute, toughening of PMMA has attracted significant attention. Brittle failure can often be avoided by incorporating a small fraction of filler particles. Core–shell composite particles composed of a rubbery core and a glassy shell have recently attracted interest as a toughening agent for brittle polymers. Here, core/shell organic–inorganic hybrid polymer nanoparticles (Si-ASA HPNs) with a silicone-modified butyl acrylate copolymer (PBA) core and a styrene-acrylonitrile copolymer (SAN) shell were used to toughen PMMA. Silicone plays dual roles as a compatibilizer and a chain extender, and it not only improves interfacial adhesion between the PBA particles and SAN copolymer, but it also increases chain entanglement of poly(acrylonitrile-styrene-acrylate) (ASA). The mechanical properties of the PMMA/ASA alloys strongly depend on the Si content, and the impact strength and elongation at break greatly improve when silicone-modified ASA is added. However, this is accompanied by loss of rigidity. Specifically, the PMMA/ASA-2 composite exhibits a good balance between toughness and rigidity, indicating that ASA-2 with 5 wt% KH570 is the most suitable impact modifier. This research provides a facile and practical method to overcome the shortcomings of ASA and promote its application in a wider range of fields.

Core/shell organic–inorganic hybrid polymer nanoparticles are synthesized by micellar nucleation, core enlarged polymerization and a grafting reaction in the system.

MIR spectral characterization of plastic to enable discrimination in an industrial recycling context: III. Anticipating impacts of ageing on identification

Ageing of polymers entails important structural changes and degrades their functional properties, particularly their aspect. Since sorting is a primordial step in recycling to achieve acceptable mechanical properties, the use of promising technologies such as MIR-HSI (Mid-Infrared Hyperspectral Imagery), which could overcome black plastics sorting issue, has to take into account the influence of ageing on identification. As ageing strongly impacts spectra, it can create confusion between materials, especially in an automatized scheme. Based on laboratory FTIR-ATR (Fourier-Transform Infrared Attenuated Total Reflection), this work investigates spectral evolutions of natural and accelerated photodegradation of Waste of Electric and Electrical Equipment plastics (WEEE) as PE, PP, HIPS, ABS and PC to help identifying a polymer despite its ageing degree. Oxidation marks were described and retrieved within a stock of about one hundred of real waste samples, then differentiated from other sources of spectral alteration as formulation. Laboratory ageing data were found to be consistent and often more extreme than real waste samples values. Generally, styrenics showed stronger spectral alteration than polyolefins despite their respective aspects. No significant spectral alteration of PC was obtained here or observed in the waste stock. As an important oxidation marker, the carbonyl peak was also found to often enable fast identification through its wavenumber. If well taken in account, ageing should not induce confusion with other polymers, even formulated, as characteristic signals are different. Finally, the different industrial sub-ranges within MIR are not affected at the same degree, possibly influencing a technological choice for industrial sorting.

Reactive Compatibilization of Polyamide 6/Olefin Block Copolymer Blends: Phase Morphology, Rheological Behavior, Thermal Behavior, and Mechanical Properties

In this study, the morphology, rheological behavior, thermal behavior, and mechanical properties of a polyamide 6 (PA6) and olefin block copolymer (OBC) blend compatibilized with maleic anhydride-grafted polyethylene-octene copolymer (POE-g-MAH) were investigated. The morphological observations showed that the addition of POE-g-MAH enhanced the OBC particle dispersion in the PA6 matrix, suggesting a better interfacial compatibility between the pure PA6 and OBC. The results of the Fourier transform infrared (FTIR) spectroscopy analysis and the Molau test confirmed the compatibilization reactions between POE-g-MAH and PA6. The rheological test revealed that the melt viscosity, storage modulus (G’), and loss modulus (G”) of the compatibilized PA6/OBC blends at low frequency were increased with the increasing POE-g-MAH content. The thermal analysis indicated that the addition of OBC had little effect on the crystallization behavior of PA6, while the incorporation of POE-g-MAH at high content (7 wt%) in the PA6/OBC blend restricted the crystallization of PA6. In addition, the compatibilized blends exhibited a significant enhancement in impact strength compared to the uncompatibilized PA6/OBC blend, in which the highest value of impact strength obtained at a POE-g-MAH content of 7 wt% was about 194% higher than that of pure PA6 under our experimental conditions.

Room temperature and low temperature toughness improvement in PBA-g-SAN/α-MSAN by melt blending with TPU

Toughness of PBA-g-SAN/α-MSAN blends at room temperature and low temperature was successfully improved by incorporating TPU elastomer.