FABRICATION AND ANALYSIS OF BIOPOLYMER BASED MATERIALS FOR PACKAGING APPLICATIONS

Abstract

Packaging is a process of preventing chemical and physical damage of the product, increasing shelf life of packaged product, preserving the product from contamination and helps in safe transportation. Various synthetic polymers are being used for packaging purposes, due to their excellent mechanical properties like tensile strength, tear strength, their barrier towards oxygen, carbon dioxide, water, aroma and so on, including easy processability and economy. However, these polymers pose various limitations due to their poor degradability and difficulty in recycling and so on. Biopolymers are fourth generation packaging materials. Due to the shortcomings of the petrochemical-based polymers and their threat to the environment, biopolymers are seen as the sustainable substitute for traditional synthetic polymers and have attracted the researchers towards the development of biopolymer-based packaging materials. Methodology Used The study aimed towards the fabrication of packaging films using biopolymer Carboxymethyl guar gum (CMG) as the base material. Various ratios of glycerol (Gly) as a plasticizer and glutaraldehyde (Glu) as a cross-linker were employed in the fabrication of these biopolymer-based films through the solution casting technique. Comprehensive characterization, such as Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR), Differential Scanning Calorimetry (DSC), Thermo-Gravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM), were conducted. The films were further examined for tensile strength, percent elongation, thickness, solubility in water, gloss, haze, and transparency. Further after conducting these tests the films were also used to find out probable applications in packaging wherein, the cut potatoes were wrapped with CMG based films and observed visually for any color change (browning) and shrinkage. v Also, to explore the possibility of commercialization of the CMG-based packaging, by varying the percentage of CMG with low density polyethylene (LDPE), the CMG LDPE blends were extruded and then injection molded as per requirement in different shapes and used for tensile strength, elongation at break, Izod impact, melt flow index, moisture content and water solubility test. Soil-degradation studies of the CMG-LDPE blends were also done through the soil burial method for a period of 84 days. Research Gap • In our literature survey it is found that the CMG based film has not yet been explored for packaging applications. • CMG-LDPE blend also has not yet been explored. • This underscored the potential novelty and unexplored possibilities in incorporating CMG into the realm of eco-friendly packaging solutions Objective The main objective of this research was to fabricate various biopolymer based films and to characterize and test them for suitability for packaging applications. The objectives of the research work were: 1. Fabrication and characterization of carboxymethyl guar gum (CMG) based material using suitable plasticizers and cross linkers for packaging applications. 2. Optimization of the process parameters for fabricated biopolymer material. 3. Assessing commercial-scale production and evaluation of properties by blending with synthetic polymers. 4. Testing of the fabricated films and blends for packaging applications. Summary of chapters The thesis is divided into six chapters and organized as follows: Chapter 1: Introduction and Literature Review. Chapter 2: Fabrication and Characterization of carboxymethyl guar gum-based (CMG) films vi Chapter 3: Evaluation of CMG-based films for packaging applications Chapter 4: Fabrication and testing of CMG-LDPE blends Chapter 5: Soil-degradation studies on CMG-LDPE blends Chapter 6: Conclusion and future scope of work Chapter 1 describes about the introduction and classification of the various biopolymers developed in the recent past, modification methods for their processing and their packaging applications are also discussed. Chapter 2 of the thesis aimed towards the fabrication of packaging films using carboxymethyl guar gum (CMG) as the base material. Various ratios of glycerol (Gly) as a plasticizer and glutaraldehyde (Glu) as a cross-linker were employed in the synthesis of these biopolymer-based films through the solution casting technique. The series of a total of 64 variants of CMG-based films were fabricated by employing the different concentrations of glycerol as a plasticizer and glutaraldehyde as a cross linker, via solvent casting technique. Further the comprehensive characterization, such as attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM), was conducted. Chapter 3 In this chapter, the information on the evaluation of CMG based films for various parameters like tensile strength, percent elongation, thickness, solubility in water, gloss, haze, and transparency is provided for exploring the possibilities of using CMG films for packaging applications. The maximum tensile strength of 37.82 MPa, maximum percent elongation of 124.20%, maximum gloss of 25.52% at a 20° angle, maximum haze of 41.93%, maximum transparency of 88.53%, and a minimum water solubility of 60.42% were observed for the developed films. This reveals that CMG-based films hold promising vii potential as a novel biomaterial for future applications in packaging, such as edible coatings and water-soluble packaging films. After conducting these tests the films were also used to find out any probable applications in packaging. The Cut potatoes were wrapped with CMG based films and observed visually for Color change (browning) & shrinkage. Chapter 4 highlights the fabrication of CMG-LDPE blends. To explore the possibility of commercialization of the CMG based packaging, the CMG-LDPE blends were fabricated by varying the percentage of CMG in the blends. The CMG powder in a varying percentage was mixed with LDPE granules using glycerol (1%) as a wetting agent. Then extruded, in a twin screw extruder, cooled and converted into small pieces. Further CMG-LDPE pieces were injection molded as per requirement in different shapes and used for the evaluation of tensile strength, elongation at break, Izod impact, melt flow index, moisture content and water solubility test. Chapter 5 revels the soil-degradation studies conducted on the CMG-LDPE blends. To have the information on the degradation of the CMG-LDPE blends, soil degradation studies of the CMG-LDPE blends has been done through soil burial method for a period of 84 days. Predetermined quantity of samples were buried 5-6 cm deep inside the soil while maintaining the moisture in the plantation soil for the period of 84 days. The samples were removed from the soil for every 7 days and tested for their soil degradability. In Chapter 6, the conclusion and future scope of the present work has been summarized. CMG-based films were successfully fabricated by utilizing glycerol as a plasticizer and glutaraldehyde as a cross-linking agent by solution casting method. Summary of findings CMG-based films were successfully fabricated by utilizing glycerol as a plasticizer and glutaraldehyde as a cross-linking agent by solution casting method. • Series of CMG-based films were successfully fabricated by utilizing glycerol as a viii plasticizer and glutaraldehyde as a cross-linking agent by solution casting method. • The reaction temperature was optimized at 75 °C by using DSC and TGA. CMG Films indicated good film forming properties at 75 °C temp. • SEM and FTIR studies indicated evidence of cross linking of CMG with glutaraldehyde. • CMG-based films were evaluated for tensile strength, elongation@ break, gloss, haze, transparency, and water solubility. • The maximum values observed for tensile strength 37.82 MPa, elongation at break 124.20%, gloss 25.52%, haze 41.93%, and transparency 88.53%. • Solubility test results indicated a minimum water solubility of 60.42% by weight which indicates the potential applications of CMG-based films in areas such as edible coatings and water-soluble packaging. • The potato wrapping study indicated the applications of CMG based films for cut fruits and vegetable packaging. • All these properties suggests the possibility of fabricated CMG-based films for packaging applications. • The CMG-LDPE blends were successfully fabricated with 10%, 20% and 30% CMG. This suggests that they can be processed on moulding machines. • The water resistance of the CMG-LDPE blends is more in comparison with its films indicates its wider packaging applications. • The CMG-LDPE blends were found to be biodegradable in soil. Soil degradability of the blends was 1.94%, 7.58% and 21.96% for 10% 20% and 30% blends respectively. This indicates environment friendliness of these blends. • Further research might enable the use of flexible use of CMG-LDPE blends for flexible packaging and rigid blends for thermoformed containers.