Finely Modulated LDPE/PS Blends via Synergistic Compatibilization with SEBS-g-MAH and OMMT

Abstract

Melt blending is an effective way to prepare new composite materials, but most polymers are incompatible. In order to reduce the interfacial tension and obtain fine and stable morphology with internal symmetric micro-textures, suitable compatibilizers should be added to the blend. The two immiscible polymers, low-density polyethylene (LDPE) and polystyrene (PS), were compatibilized by styrene/ethylene/butylene/styrene block copolymers grafted with maleic anhydride (SEBS-g-MAH) and organomontmorillonite (OMMT). The scanning electron microscope results indicated that the size of the PS phase decreased with increasing the content of SEBS-g-MAH. By introducing OMMT into LDPE/PS/SEBS-g-MAH composites, the compatibility of composites was further improved. The rheological analysis and Cole–Cole plot analysis indicated that the addition of SEBS-g-MAH and OMMT increased the interaction between the two phases. The tensile strength, elongation at break, and impact strength of the LDPE/PS/SEBS-g-MAH (70/30/7, wt%) composite increased by 64%, 255%, and 380%, respectively, compared with the LDPE/PS (70/30, wt%) composite. A small amount of OMMT could synergistically compatibilize the LDPE/PS composite with SEBS-g-MAH. After adding 0.3% OMMT into the LDPE/PS/SEBS-g-MAH system, the tensile strength, elongation at break, and impact strength of the composite were further increased to 18.57 MPa, 71.87%, and 33.28 kJ/m2, respectively.

A Compatibilizing Strategy for Upcycling Polyethylene and Polystyrene with Ethylene/(Phenyl Functionalized α-Olefin) Copolymers Containing Continuous Comonomer Segments

“…Compatibilizers could open promising opportunities for upcycling recovered PE/PS into higher-value or available materials with lower sorting costs. On the basis of fundamentals of compatibilization, the most desirable compatibilizers for PE/PS blends would be diblock, multiblock, and graft copolymers of ethylene and styrene (or other phenyl functionalized α-olefins). ,− But the synthesis of pure E-St copolymers (either random or block) are much difficult and usually result in the formation mixtures of E-St copolymers along with homopolymers (PE and PS) by using industrial titanium-based catalyst systems. ,,, Considerable efforts have been made to seek or synthesize new compatibilizers to improve the compatibilization of PE and PS. Due to the lack of pure E-St block copolymers, early studies about the compatibilities of PE and PS were focused on the commercially available compatibilizers, such as butadiene-styrene copolymer (SB), , hydrogenated butadiene-styrene copolymer (SEB), and styrene-(ethylene/butylene)-styrene triblock copolymer (SEBS, i.e., hydrogenated styrene–butadiene-styrene copolymer). − These copolymers are efficient in reducing the size of the dispersed phase, but the mechanical properties of HDPE/PS/copolymer blends improve little in comparison to HDPE/PS blends.…”

Relaxation Functions Interpolating the Cole–Cole and Kohlrausch–Williams–Watts Dielectric Relaxation Models

“…Recently, this model was used to derive a generalized skin depth formula of the polarized media in frequency-domain electromagnetic detection, and the method can be applied to the calculation of electromagnetic wave propagation depths in complex dispersive media [8]. In [9], the compatibility of composite materials was considered through a rheological analysis and Cole-Cole plot analysis. Other generalized relaxation models proposed in the frequency domain include the Davidson-Cole model [4], the Havriliak-Negami model [5], etc.…”