Reactive Compatibilization of PA6/LDPE Blends with Glycidyl Methacrylate Functionalized Polyolefins

Abstract

Summary: Blends of polyamide‐6 (PA6) and low density polyethylene (LDPE) were compatibilized by melt mixing with various polyolefins functionalized with glycidyl methacrylate (GMA), i.e., GMA grafted LDPE (LDPE‐g‐GMA), GMA grafted styrene‐ethylene/butylene‐styrene block copolymer (SEBS‐g‐GMA) and ethylene‐co‐glycidyl methacrylate copolymer (E‐GMA). Blends with PA6/LDPE composition ratios of 25/75 and 75/25 wt.‐%/wt.‐% were prepared in a Brabender internal mixer and their properties were evaluated by SEM, rheological measurements and DSC. Morphological investigation by SEM showed a neat improvement of phase dispersion and interfacial adhesion in all compatibilized blends when compared to PA6/LDPE binary blends. The variation of the dispersed phase size was analyzed as a function of blend composition, compatibilizer concentration and GMA content. The emulsification curves of compatibilized blends showed that the equilibrium size of dispersed particles at the saturation concentration of copolymer was lower when PA6 was the major component. The finest dispersion of the LDPE phase (<0.25 μm) was observed in the presence of SEBS‐g‐GMA copolymer. LDPE‐g‐GMA and E‐GMA displayed a similar compatibilizing efficiency. In all cases, the blends with a polyamide matrix presented a marked rise in torque and melt viscosity with increasing compatibilizer content. These effects were accounted for by a reaction between the epoxide groups of LDPE‐g‐GMA and the carboxyl/amine end‐groups of PA6, leading to the formation of an interchain graft copolymer. The phase transition processes of PA6 in the blends were influenced by the compatibilizer content and the interfacial interactions between the polymer components, suggesting a different role for the compatibilizer at the PA6/LDPE interface.SEM micrograph of PA6/LDPE 25/75 blend compatibilized with 2.5 phr SEBS‐g‐GMA.magnified imageSEM micrograph of PA6/LDPE 25/75 blend compatibilized with 2.5 phr SEBS‐g‐GMA.

On the Preparation and Characterization of Polyethylene/Polyamide Blends by Melt Processing in the Presence of an Ethylene/Acrylic Acid Copolymer and of New Phosphazene Compounds

“…[5][6][7][8][9] A low-molecular-weight bisoxazoline compound has also been successfully used together with EAA to enhance the formation of compatibilizers by in situ reactions. [10] Similar successful results have been obtained by using PE functionalized with glycidyl methacrylate, [9,11,12] with other methacrylic compounds, [11,13] or with maleic anhydride. [14,15] Cyclo(organo)phosphazenes (CP) are low-molecularweight phosphazene derivatives, whose cyclic structure is formed by repeating -P--N units, each phosphorus bearing two substituent groups (usually, but not necessarily, organic in nature).…”

Role of the interphase in the flow stability of reactive coextruded multilayer polymers

“…The advantages of using GMA functionalization include the faster grafting reaction onto polyolefins when compared with that of maleic anhydride or acrylic acid. Moreover, the bulky structure of GMA is believed to reduce crosslinking and chain scission within the polymer backbone [27]. Another important aspect is that the formation of water does not occur during the reaction of the epoxide ring with À ÀCOOH or À ÀNH2 groups of PA in the melt, thus preventing the hydrolysis of chain bonds formed at the interface.…”

Melt Mixing of Ethylene/Butyl Acrylate/Glycidyl Methacrylate Terpolymers with LDPE and PET

“…It is also reported that the bulky structure of GMA is believed to reduce crosslinking and chain scission in the polymer backbone. [22,23] In a previous paper, [24] we reported some results on the use of an ethylene/butyl acrylate/glycidyl methacrylate (EBAGMA) terpolymer as compatibilizer for LDPE/PET blends in virgin and recycled materials. In both virgin and recycled materials, the results showed that the addition of 15 wt.-% of EBAGMA terpolymer to 70/30 LDPE/PET blends produced better dispersion of PET particles in the LDPE matrix, reducing the size domains of PET and with a slight increase in the ultimate mechanical properties.…”