Synthesis of Master Batch from Modified Gum Arabica and Modified Euphorbia Trigona Mill for Development of Poly (Lactic Acid) based Bio Composite

Abstract

Environmental pollution caused by the widespread use of petroleum based polymers brought the need to replace the petro-based polymers with bio based polymers made from renewable resources due to their degradability. Among these, Polylactic acid (PLA) is a well-known biodegradable, biocompatible and sustainable polymer, derived from renewable agricultural sources. However, its wide range of applications (packaging) is constrained by low crystallization rate, poor mechanical properties and low thermal stability. The main aim of this research was to investigate the effect of modified gum Arabica (GA), euphorbia trigona mill latex (ETML) and its master batch on PLA properties. In this context, this work demonstrates modification of both gum arabic and euphorbia trigona mill with lactic acid oligomer by in situ condensation polymerization. Effect of different reaction conditions such as; reaction temperature, mixing ratio and reaction time on grafting efficiency and percentage solubility of synthesized bio-conjugate have been investigated and grafting reaction was confirmed by FTIR and NMR. A modified gum Arabica, euphorbia trgona mill latex and master batch dispersed PLA (PLA/OLLA-g-GA, PLA/OLLA-g-ETML and PLA/master batch) bio composite films were prepared by solution casting method. After incorporating modified gum Arabica, euphorbia trgona mill latex and master batch into the PLA matrix, the effect of modified gum Arabica, euphorbia trgona mill latex and master batch on the tensile strength, elongation at break, rate of crystallization, transmittance, thermal stability, and anti-microbial properties of PLA was investigated. Surface morphology of different fillers loading dispersion in the PLA matrix was analyzed by optical microscopy. The ultraviolet-visible (UV-Vis) result implies that the transmittance of neat PLA, PLA/OLLA-g-GA(3%),PLA/ OLLA-g-ETML(5) and PLA/ master batch bio composite film was 55.6%,25.2,27.4 and 64.76 at 600 nm, respectively, which indicates the decrement in transmittance. The antibacterial activities of PLA/OLLA-g-GA,PLA/ OLLA-g-ETML and PLA/ master batch bio composite film were evaluated against Gram-positive bacteria (S. pyogenes and S. aureus) and Gram-negative bacteria (E. coli and P. aeruginosa) and it was observed that a higher zone of inhibition which suggests the prepared films could be used as antimicrobial packaging materials.

XV The tensile strength was improved by 38.31, 10.47 and 47% with the addition of OLLA-g-GA (3%), OLLA-g-ETML (5%) and master batch (OLLA-g-GA (3%) OLLA-g-ETML(5%), respectively. The elongation at break also enhanced by 20.62 and 34% with the addition of OLLA-g-GA (3%), OLLA-g-ETML (5%) and master batch (OLLA-g-GA (3%) - OLLA-g-ETML (5%), respectively. The results from DSC showed that after introducing the nucleating agents into PLA, the crystallinity in all samples was improved. The highest crystallinity at 45.83% was obtained from PLA /master batch. Effect of annealing time on degree crystallinity was also investigated. The thermogravimetry analysis (TGA) reveals that the thermal stability PLA after incorporating modified GA and ETML increased but with addition of master batch. Thermal degradation behavior of neat PLA and PLA/master batch films was investigated using different kinetics models. The activation energies of both neat PLA and PLA/master batch were estimated using isoconversiconal Augis & Bennet, Kissiger, Frediman(FD), Kissinger-Akahira-Sunose (K-A-S) and Flynn-Wall-Ozawa (F-W-O) method, the mechanism of thermal degradation was elucidated by Coats-Redfern method. The activation energy PLA/master batch bio-composite film was lower for all model compared to neat PLA.Environmental Pollution Caused By The Widespread Use Of Petroleum Based Polymers Brought The Need To Replace The Petro-Based Polymers With Bio Based Polymers Made From Renewable Resources Due To Their Degradability. Among These, Polylactic Acid (Pla) Is A Well-Known Biodegradable, Biocompatible And Sustainable Polymer, Derived From Renewable Agricultural Sources. However, Its Wide Range Of Applications (Packaging) Is Constrained By Low Crystallization Rate, Poor Mechanical Properties And Low Thermal Stability. The Main Aim Of This Research Was To Investigate The Effect Of Modified Gum Arabica (Ga), Euphorbia Trigona Mill Latex (Etml) And Its Master Batch On Pla Properties.In This Context, This Work Demonstrates Modification Of Both Gum Arabic And Euphorbia Trigona Mill With Lactic Acid Oligomer By In Situ Condensation Polymerization. Effect Of Different Reaction Conditions Such As; Reaction Temperature, Mixing Ratio And Reaction Time On Grafting Efficiency And Percentage Solubility Of Synthesized Bio-Conjugate Have Been Investigated And Grafting Reaction Was Confirmed By Ftir And Nmr. A Modified Gum Arabica, Euphorbia Trgona Mill Latex And Master Batch Dispersed Pla (Pla/Olla-G-Ga, Pla/Olla-G-Etml And Pla/Master Batch)Bio Composite Films Were Prepared By Solution Casting Method. After Incorporating Modified Gum Arabica, Euphorbia Trgona Mill Latex And Master Batch Into The Pla Matrix, The Effect Of Modified Gum Arabica, Euphorbia Trgona Mill Latex And Master Batch On The Tensile Strength, Elongation At Break, Rate Of Crystallization, Transmittance, Thermal Stability, And Anti-Microbial Properties Of Pla Was Investigated. Surface Morphology Of Different Fillers Loading Dispersion In The Pla Matrix Was Analyzed By Optical Microscopy. The Ultraviolet-Visible (Uv-Vis) Result Implies That The Transmittance Of Neat Pla, Pla/Olla-G-Ga(3%),Pla/ Olla-G-Etml(5) And Pla/ Master Batch Bio Composite Film Was 55.6%,25.2,27.4 And 64.76 At 600 Nm, Respectively, Which Indicates The Decrement In Transmittance. The Antibacterial Activities Of Pla/Olla-G-Ga,Pla/ Olla-G-Etml And Pla/ Master Batch Bio Composite Film Were Evaluated Against Gram-Positive Bacteria (S. Pyogenes And S. Aureus) And Gram-Negative Bacteria (E. Coli And P. Aeruginosa) And It Was Observed That A Higher Zone Of Inhibition Which Suggests The Prepared Films Could Be Used As Antimicrobial Packaging Materials. XvThe Tensile Strength Was Improved By 38.31, 10.47 And 47% With The Addition Of Olla-G-Ga (3%), Olla-G-Etml (5%) And Master Batch (Olla-G-Ga (3%) Olla-G-Etml(5%), Respectively. The Elongation At Break Also Enhanced By 20.62 And 34% With The Addition Of Olla-G-Ga (3%), Olla-G-Etml (5%) And Master Batch (Olla-G-Ga (3%) - Olla-G-Etml (5%), Respectively .The Results From Dsc Showed That After Introducing The Nucleating Agents Into Pla, The Crystallinity In All Samples Was Improved. The Highest Crystallinity At 45.83% Was Obtained From Pla /Master Batch. Effect Of Annealing Time On Degree Crystallinity Was Also Investigated. The Thermogravimetry Analysis (Tga) Reveals That The Thermal Stability Pla After Incorporating Modified Ga And Etml Increased But With Addition Of Master Batch. Thermal Degradation Behavior Of Neat Pla And Pla/Master Batch Films Was Investigated Using Different Kinetics Models. The Activation Energies Of Both Neat Pla And Pla/Master Batch Were Estimated Using Isoconversiconal ?Augis & Bennet, Kissiger, Frediman (Fd), Kissinger-Akahira-Sunose (K-A-S) And Flynn-Wall-Ozawa (F-W-O) Method, The Mechanism Of Thermal Degradation Was Elucidated By Coats-Redfern Method. The Activation Energy Pla/Master Batch Bio-Composite Film Was Lower For All Model Compared To Neat Pla.