Fabrication And Characterization Of Novel Polymer/Organo-Mmt (Organo-Silica)/ Biopolymer Nanocomposite Blends By Reactive Extrusion

Abstract

ABSTRACT

FABRICATION AND CHARACTERIZATION OF NOVEL POLYMER/ORGANO-MMT (ORGANO-SILICA)/BIOPOLYMER NANOCOMPOSITE BLENDS BY REACTIVE EXTRUSION

Bayram Ali GÖÇMEN

Doctor of Philosophy, Department of Nanotechnology and Nanomedicine

Supervisor:Prof. Dr. Günay Kibarer

(Prof. Dr. Z.M. O. Rzayev)

January 2018, 136 pages

Recently, polymer nanocomposites have attracted great attention of industrial and academic society to get different kind of enforced valuable material. Biodegradable nanocomposites of different polymers are also in focus during new product development due to environmental concerns and regulations. Material properties of polymers can be enhanced dramatically by incorporating layered silicates and biodegradation can be suited with lactic acid or caprolactone based polymers together with suitable compatibilizers and fillers. Different kinds of formation of layered nanocomposite typematerials frequently exhibits remarkable improvements, such as high storage modulus, tensile, and flexural properties, decrease in gas permeability and flammability or fire retardency and provide an increase in the biodegradability. In this study, novel isotactic polypropylene (PP) based multi-functional nanocomposites were fabricated in melt by a one-step reactive extrusion using a Rondol twin-screw extruder at preoptimized processing conditions and investigated in situ chemical and physical processes occurring during the extrusion of multifunctional polymer blend compositions. The compositions of reactive blends include PP as a matrix polymer,PP-g-MA graft copolymer as a reactive compatibilizer, copolymer covalently encapsulated silica nanoparticles (NPs) as reactive nanofiller-compatibilizer, and intercalated biodegradable poly (D, L-lactide) (PLA) or poly (ɛ-caprolactone) (PCL) silicate layers nanocomposites using ODA-MMT as a reactive or DMDA-MMT as a non-reactive nanofillers. The chemical and physical structures, morphology, thermal behaviors and mechanical and rheological properties (shear stress and viscosity) as well as effects of origin organoclay and polyester, and copolymer encapsulated silica NPs on the main properties of nanocomposites were investigated by FTIR, solid state 13C and 29Si NMR, XRD, SEM-TEM, DSC-TGA and DMA (shear stress and viscosity) analysis methods, respectively. There was demonstrated that the essential improvement of crystallinity, thermal stability, rheological and mechanical parameters, surface and internal morphologies of the nanocomposites as compared with those for a matrix polymer. Better results were observed for nanocomposites containing reactive organoclay and PCL polyester. Colloidal copolymer-silica NPs showed a well dispersion effect on structure of new polypropylene composites due to interactions of molecular bonds between different layers. Similarly, together with PP based pristine polymer, investigations made on multifunctional polymer blend nanocomposites (NCs) consisting EPDM elastomer as a matrix polymer, bioengineering polyesters (PLA and PCL), PP-g-MA compatibilizer and covalently encapsulated colloidal alternating reactive copolymer-g-APTS (-aminopropyl trimethoxysilane)-silica nanoparticles (NPs) as reactive compatibilizer-nanofillers, and organoclays (reactive ODA-MMT and complexable DMDA-MMT) nanofillers that were fabricated in melt by a one-step reactive extrusion nanotechnology. The chemical and physical structures, morphology, thermal behaviors, mechanical and rheological properties of NCs, as well as effects of origin organically and polyester, and colloidal copolymer-g-silica (NPs) on the main properties of the nanocomposites were confirmed again by FTIR, solid state 13C and 29Si NMR, XRD, SEM-TEM, DSC-TGA and dynamic rotary rheometric analysis methods. The effects of bioengineering polyesters and their molecular mass, origin of organology, and reactive PP-g-MA compatibilizer were evaluated. Moreover, colloidal copolymer-g-silica NPs as reactive compatibilizer-nanofiller play an important role in the formation fine dispersed morphology on nanocomposites structure of polymer blends. This structural occurrence is due to affective in situ physical and chemical interactions in multifunctional polymers/nanofillers blends. These interactions occur in the chosen lower temperatures of the five barrier zones at 120oC, 130oC and 130oC, 145oC and 145oC during aone-step cycle (around 5-10 min) of reactive extrusion processing. Chemistry and physics of in-situ interfacial interactions in multifunctional NCs during extruding process were also estimated. These interactions of bonds due to multifunctional groups of reactive compatibilizers and silica copolymers inside nanocomposite material show behaviourdifference on thermal, rheological properties compared to pristine polyesters/polymers.

Keywords: PP, PP-g-MA, EPDM rubber, polyesters, silica NPs, organoclays, reactive extrusion, structure-composition-property relationships, morphology, thermal stability, shear stress, rheology, bioengineering polyesters, copolymer-g-silica NPs, nanocomposites, reactive extrusion nanotechnology, polymer compatibilizer, nanostructure-composition-properties relationships.