NPTEL Local Chapter  MACFAST FOOD TOXIN PORTAL
        



Production of Reinforced Bioplastics

Integrated Technology for the Production of Reinforced Bioplastics with Celluloses of Plant Origin

  Introduction:

                  Natural cellulose-based fibres are gaining important attention for their diversified applications in engineering and their uses, such as building materials and structural parts for the automotive application, where light weight is required. The main constituent of natural fibre is cellulose. Hydrogen bonding between cellulose molecules provides the necessary strength and stiffness to the fibres. The overall structure can be highly crystalline depending upon the source and thereby highly impermeable for penetrant. Amorphorous regions, however, do exist within the fibrils and between the fibrils and bundles, where pectin, hemicelluloses and liginin act as matrix substances1. Many agricultural by-products from agricultural activities and agro-based processing litter the environments and constitute waste problems. Today it is burnt, buried or composted. Such agro wastes being organic in nature are also a source for carbon and a host of other useful materials and chemicals, particularly for the production of bio-materials. Reinforcement of cellulose with conventional plastics is a promising option to reduce the problems arisen from the agro wastes produced by related industries. Moreover, cellulose is a bulk commodity, which makes it inexpensive and available in sufficient volume for the large scale production of reinforced plastics. The rationale behind the use of cellulose as reinforcement in polymers is that upon disposal, the cellulose molecules will be consumed by microbes and thus reduce the volume of the disposed article, correspondingly it reduces the material cost too.

     Because of its fibrous structure and other physical and chemical properties, cellulose is extensively used in industry in various forms. But in nature, cellulose seldom occurs in the free state -it is generally associated with other compounds such as lignin, pectin etc. Hence the isolation of cellulose from natural fibers is important in this context.

                 Even though several works have been reported, development of biocomposites from conventional plastics and natural fibres, those with powdered cellulose from natural fibres and natural agricultural residues as reinforcement are rarely done.

Methodology

Materials

            Used Jute bags were collected form cashew nut industries located in Kerala. Eichornia  (water Hyasinth) were collected from local stagnated water. Chemicals: Sulfuric acid 98% Pure, M=98.08 g/mol (Merck), LDPE, maleated PE, PE glycol, sodium chlorite, acetic acid.

Methods

Preparation of cellulose powder from Eichornia:-

                                  The stems of the Eirchonia were cut into approximately 2-4 cm in length and washed thoroughly with water to avoid the impurities. It was then treated with NaOH(2%) followed by washing with water. The alkali treated eichornia was then subjected to bleaching with hydrogen peroxide(5%). The bleached eichornia was again washed with water and dried in a hot air oven at 600C. Acid treatment of the dried eichornia with sulphuric acid was done and is washed with water for several times until the PH was neutral and again kept in the oven for drying. The dried fibers were taken out and crushed into fine powder.

Preparation of cellulose from jute fiber from jute sack & residues:        

                            Used Jute sack residues were first subjected to alkali treatment with NaOH and then washed with water. Alkali treated jute sack and jute waste was then bleached with hydrogen peroxide (30%) followed by washing and drying. The dried sack residues were acid treated with conc. Sulfuric acid and washed with water until a pH of 7. The neutralized jute fibers were then drived in a hot air oven(24hrs) and are crushed into fine powders.

Estimation of holocellulose (from jute, cotton, pandanus and eichornia)

                         5.000 g of powdered fiber was added to a 250 mL beaker, containing 0.7500 g of sodium chlorite, 0.5 mL of concentrated acetic acid, 100 mL of distilled water was then added and the mix was stirred until the chlorite dissolved. The beaker was then covered with a watch glass and placed on a thermostat bath at 750C for 1 h with occasional stirring. The same amount of reagents was added to the beaker every hour for 2 more hours, totalizing a digestion period of 3 h. The system was cooled to 100C in ice water, and then filtered through a sintered crucible. The material was now nearly completely white. The residue was washed six times with ice water and dried in an oven at 1050C for 6 h. After this period, the residue was weighed to quantify the holocellulose.

 EXPERIMENTAL:

                          The following formulations were developed by melt blending technique using make Bernstorff Co-rotating principle extruder. Extrudate were granulated into 3 mm length by cutter which wad used for molding of test specimens and components.

 Formulation 1: LDPE (16MA 400) (50%) + LDPE-g-MA (Optim E-142) (10%) + Jute      Plant powder (40%)

 Formulation 2: LDPE (16MA 400) (50%) + LDPE-g-MA (Optim E-142) (10%) + Eichornia plant powder (40%)

                Specimens were tested for Tensile strength & Modulus, Elongation, Impact strength, Flexural Strength & Modulus were using JSW-75 Injection moulding machine and components such as Hangers & Disc cutleries and cups are also moulded by Injection moulding machine.

                  Performance Evaluation of the above composites was carried out by testing the specimen using various ASTM D Test Methods.

The following are the test values: 

S.NO.

DETAILS OF TEST

TEST METHOD

OBTAINED RESULTS

UNIT

Formulation 1

Formulation 2

1.

Tensile Strength

ASTM D 638

10.73

7.91

MPa

2.

Elongation

ASTM D 638

5.65

6.73

%

3.

Flexural Strength

ASTM D 790

12.74

9.44

MPa

4.

Izod Impact

ASTM D 256

32.58

31.82

J/m

5.

Water Absorption

ASTM D 570

0.43

0.33

%

 CONCLUSION: 

                    Plant Powder from Jute & Eichornia samples filled LDPE composites were developed which can be used for disposable products. The performances of the above composites indicate that Jute plant powder filled LDPE Biocomposites is superior in comparison with Eichornia. The plant powder filled LDPE composites can be used for disposable biodegradable applications.