Compatibilizing effect of EPM-g-MA in EPDM/poly(trimethylene terephthalate) incompatible blends

Impact of γ-irradiation and SBR content in the compatibility of aminated (PVC/LLDPE)/ZnO for improving their AC conductivity and oil removal

In some cases, blends containing PVC and LLDPE show low compatibility. Adding styrene-butadiene rubber to the PVC/LLDPE mixtures leads to a noticeable increase in tensile strength and compatibility of the blends. Also, an improvement in tensile strength is observed after incorporating SBR compatibilizer resulting in entirely different gamma irradiation doses. Without a compatibilizer, the mixture exhibits a distributed PVC and LLDPE phase with variable sizes and shapes; even a sizable portion of the domains resemble droplets. Styrene butadiene rubber (SBR) and gamma radiation make mixtures of (PVC/LLDPE) more compatible. The SEM study of the blends demonstrated that adding the compatibilizer resulted in finer blend morphologies with less roughness. At the same time, gamma irradiation reduced this droplet and gave a more smooth surface. Poly(vinyl chloride) (PVC) was chemically modified with four different amino compounds, including ethylene diamine (EDA), aniline (An), p-anisidine (pA) and dimethyl aniline (DMA) for improving the electric conductivity and oil removal capability of the blend polymer. All ionomers were prepared by nucleophilic substitution in a solvent/non-solvent system under mild conditions. This work novelty shows a sustainable route for producing oil adsorption materials by recycling plastic waste. After the amination process of poly(vinyl chloride) the oil adsorption was significantly enhanced.

ADVANCES IN TECHNIQUES AND APPLICATIONS OF RUBBER SURFACE GRAFTING MODIFICATION

To meet the requirement in the application of medical devices, composites, biomaterials, corrosion resistance, and selective adsorptions, rubber surface modification is usually indispensable. Grafting treatment is one of most significate treatment methods. In this paper, we focus on rubber surface grafting modification, including grafting techniques and applications. Different grafting methods—including monomer grafting polymerization and coupling reaction—are covered and compared briefly. The related applications of surface grafting modification techniques, such as improving compatibility of waste rubber as fillers, hydrophobicity and lipophilicity of sponge rubber for oil–water separation, biocompatibility of rubber in the medical field, and forming surface patterns, are demonstrated in detail. The new research directions of surface grafting techniques as well as main challenges in application are also discussed.

Unique Compatibilized Thermoplastic Elastomer with High Strength and Remarkable Ductility: Effect of Multiple Point Interactions within a Rubber-Plastic Blend

In the case of thermoplastic elastomers (TPEs) based on nonpolar polypropylene (PP) and polar rubbers, a small quantity of a third component known as the compatibilizer is added to maximize the compatibility between the incompatible blend components. Generally, one part of the compatibilizer reacts with the nonpolar PP phase and the other part of the compatibilizer reacts with the polar rubber phase, which in turn produces TPEs with useful properties. Till today, there have been no reports in the literature that examine the effect of a compatibilizer that can have multifaceted interactions with the incompatible blend components for the development of TPEs with unique properties. Accordingly, here, an ethylene-acrylic ester-maleic anhydride terpolymer (E-AE-MA-TP) has been used as the compatibilizer for the preparation of TPEs based on nonpolar isotactic polypropylene (i-PP) and polar epichlorohydrin rubber (ECR). The E-AE-MA-TP compatibilizer contains ethylene groups, acrylic groups, and anhydride/acid groups along its backbone, which act as the sites for establishing multifaceted interactions with both i-PP and ECR. The compatibilization efficiency of the E-AE-MA-TP compatibilizer has been analyzed by contact angle measurements, Fourier transform infrared (FTIR) spectroscopy, tensile stress-strain studies, mixing torque profiles, rheological studies, differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM) images. The particle size of the dispersed ECR domains in the i-PP matrix of the i-PP/ECR blend prominently decreases (∼90% reduction) by incorporation of a very low dosage (5 wt %) of the E-AE-MA-TP compatibilizer. The i-PP/ECR (40 wt %/60 wt %) blend containing 5 wt % compatibilizer displays outstanding mechanical properties (especially strain at break value (∼370%)), which are superior to the mechanical properties of several compatibilized TPEs (based on PP and polar rubbers) reported in the literature. The unique properties of TPEs based on i-PP and ECR in the presence of the E-AE-MA-TP compatibilizer is attributed to the efficacy of the E-AE-MA-TP compatibilizer to establish multifaceted interactions with both i-PP and ECR.

Modification of substandard EPDM with amorphous thermoplastic polyesters (PETG and PEF): microstructure and physical properties

The phase morphology, thermal behavior and mechanical properties of two series of polymer blends based on ethylene/propylene/diene rubber (EPDM) and amorphous homologues of poly(ethylene terephthalate), i.e. glycol modified poly(ethylene terephthalate) (PETG) and poly(ethylene furanoate) (PEF), were investigated. The morphology of the blends shows a two phase structure in which the minor phase (amorphous polyester) is dispersed as domains in the major (EPDM) continuous matrix phase. Differential calorimetry studies confirmed that both systems were immiscible and exhibits two glass transitions. The melting peak area of EPDM in the blends decreased as the amount of the other component increased. The values of stress at strain of 100% were improved upon the increasing content of PETG in EPDM system, while only slight decrease of this value was observed. Moreover, the strong improvement of hardness and thermo-oxidative stability along with an increasing content of amorphous polyester phase was reported.

Interfacial tension of reactive, liquid interfaces and its consequences

Dispersions of immiscible liquids, such as emulsions and polymer blends, are at the core of many industrial applications which makes the understanding of their properties (morphology, stability, etc.) of great interest. A wide range of these properties depend on interfacial phenomena, whose understanding is therefore of particular importance. The behaviour of interfacial tension in emulsions and polymer blends is well-understood - both theoretically and experimentally - in the case of non-reactive stabilization processes using pre-made surfactants. However, this description of the interfacial tension behaviour in reactive systems, where the stabilizing agents are created in-situ (and which is more efficient as a stabilization route for many systems), does not yet find a consensus among the community. In this review, we compare the different theories which have been developed for non-reactive and for reactive systems, and we discuss their ability to capture the behaviour found experimentally. Finally, we address the consequences of the reactive stabilization process both on the global emulsions or polymer blend morphologies and at the interfacial scale.

Morphological explanation of high tear resistance of EPDM/NR rubber blends

The fatigue properties of cross-linked blends of ethylene propylene diene rubber (EPDM) with low natural rubber (NR) content and reinforced with carbon black (CB) are studied. It is found that such EPDM/NR compounds have superior crack growth resistance and fatigue lifetime. For low NR contents, transmission electron microscopy reveals that the NR phase forms small droplets of 20-50 nm. Remarkably, these droplets are even smaller than the primary CB particles. Atomic force microscopy shows that the the NR phase droplets have a higher loss factor and a smaller elastic modulus than the surrounding EPDM matrix. Rheometer measurements are used to study the effect of the phase morphology on the rubber mechanical properties. These rheological data are compared with the prediction of the Eshelby model describing the effect of elastic inclusions on solids. A complex interplay between the rubber phase morphology and the solubility of both the sulfur cross-linking system and CB is observed, which cannot be predicted theoretically. It is proposed that the soft NR droplets effectively inhibit the crack propagation in the EPDM matrix.

An efficient strategy to develop microwave shielding materials with enhanced attenuation constant

PMMA wrapped MWNTs were employed to design microwave shielding materials with enhanced attenuation constant in PC/SAN blends.

Enhancing the Mechanical Properties of Cross-Linked Rubber-Toughened Nanocomposites via Electron Beam Irradiation

Improving the mechanical properties of a pristine system is the main target of developing nanocomposites. The nanocomposites systems were first prepared via intercalation technique with different organophilic montmorillonite (OMMT) loading. Two types of cross-linking techniques were applied, namely, as maleic anhydride polyethylene (MAPE) and electron beam (EB) irradiated system. The effectiveness of these systems was then compared with the control one and analyzed based on the mechanical tests and morphological examination. The mechanical tests revealed that control, MAPE, and EB irradiated systems had attained the optimum mechanical properties at 4 vol% OMMT content. EB irradiated unit of a dose of 100 kGy showed excellent mechanical properties with higher crosslinking degree which were proved by gel content analysis. X-ray diffraction (XRD) analysis confirmed the existence of delamination structure with MAPE and EB irradiation techniques based on the disappearance of characteristic peak. The degree of delamination was further investigated by transmission electron microscope (TEM).

Reaction kinetics and macromolecule-metal chelate complex formation in metal containing semi-interpenetrating polymer networks based on crosslinked polyurethane and linear polymethylmethacrylate

According to DSC and EPR data kinetics of formation of simultaneous semi-interpenetrating polymer networks based on crosslinked polyurethane and linear polymethylmethacrylate with 50:50 and 70:30 ratio obtained in the presence of 3d-metal chelates depends on type of metal. On the other hand system composition determines polyurethane or polymethylmethacrylate selection during formation of complexes with metal -diketonates.