3D fibrillated network of compatibilized linear low density polyethylene/polyamide with high melt strength and superior foamability. (16th July 2021)

• Record Type: Journal Article
• Authors: Mohammadi, Raziyeh S.; Zolali, Ali M.; Kim, Jung-Hyun; Jalali, Amirjalal; Park, Chul B.
• Is Part Of: Polymer. Volume 228(2021)
• Publication Date: 2021-07-16
• Subjects: Polyethylene -- Melt strength -- Foamability -- Nanofibrillation -- Compatibilizer -- Crystallinity; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.123911
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: A new, efficient and easy to scale up approach to enhance the melt strength of linear low density polyethylene (LLDPE) through high aspect ratio polyamide (PA) fibrillar inclusions is presented. For the first time, the effect of the incorporation of compatibilizer in the blends on the efficiency of the in-situ fibrillation approach to improve rheological properties and foamability is discussed. The morphological analysis indicates high aspect ratio fibers were achieved for both compatibilized and non-compatibilized systems. Also, very fine fibers with nano-scale cross-sectional diameter were achieved for compatibilized blends. Comparable rheological responses and substantial improvement of the foaming ability with superior foam morphology and high cell density was obtained, for both fibrillated blends with and without compatibilizer. Investigation of the crystallinity of the blends through DSC and WAXD indicated that bimodal melting and crystallization of LLDPE is remarkably affected by the presence of PA inclusions, particularly for the blends containing fibrillated PA. Further investigation of the crystallinity through 2D-SAXS revealed formation of shish-kebab crystalline structures as a result of drawing and shear induced crystallization. Graphical abstract: Image 1 Highlights: Melt strength and foaming ability of LLDPE drastically improved by incorporation of a small amount of polyamide nanofibrils. High aspect ratio PA fibrils renders blends with favorable rheological properties in blends with and without compatibilizer. Higher cell density foams are achieved for blends with fibrillar morphology compared to blends with droplet morphology. Shish-kebab crystalline structures are formed as a result of drawing and shear induced crystallization.