BioplasticsSynthesis of polymeric films

using waste banana peels

Abhijit Mohapatra 60011100028

Hemant Sharma 600011100054

Shruti Prasad 60011100034

Why Banana Peels?

Objective of the Project

The Objective of this project was to synthesize bio-polymeric

films from banana peels and identify the ideal combination of

parameters which would give the maximum tensile strength to

the sample.

The parameters considered were :

i. pH of the reaction mixture

ii. Residence time for hydrolysis of the reaction mixture

iii. Choice of plasticizer

Procedure for Synthesis

Preparation of Banana Paste

Boiling Decant water Drying Grindin

g

Production of Film

25gm Paste

Add 3ml HCl

Add 2ml Plasticize

r

Add NaOH Baking Polymeri

c film

Reaction Mechanism

Starch consists of two different types of polymer chains:

1. Branched chained amylopectin

2. Linear Chained Amylose

Hydrolysis

Amylose is a straight polymer, a desirable

polymer to make plastic

Amylopectin is branched polymer which

makes the plastic brittle

Acid Hydrolysis is done to break the branched

chains of amylopectin to aid plastic formation

Addition of Plasticizer

The Plasticizer gets in between the

polymer chains and prevents them from

lining up in rows to form a crystalline

structure.

The Plasticizer increases flexibility, and

develops the plasticity of the product.

Addition of NaOH

If hydrolysis time is prolonged,

amylose also gets hydrolysed

Hence, NaOH is added to neutralize

the Acid

Phase wise Synthesis

Stage 1: pH and Residence time were varied keeping

plasticizer same. Best combination obtained by strength

test was used for Stage.

Stage 2: Based on the values of parameters obtained,

Fresh samples were prepared. This time Plasticizers were

changed. Plasticizers used were:

• Glycerine

• Sorbitol

• Polyethylene glycol (PEG)

Trials Conducted

9 Experimental trials were conducted, out of this 3

were accepted for testing

Reasons for discarding samples:

• Perforations on the sample

• Incomplete baking

• Incorrect Concentration of reagents

Procedure: Tensile Strength Test

Step 1: Visual inspection

Step 2: The approved sample is cut

into a 2cm by 4cm rectangular slice

Step 3: The samples are clamped such

that 60% of the sample is our testing

region

4cm Sample

20%

 

60%

20%

  2 cm  

Step 4: After sample is clamped, weights are added in

Steps of 10gm with 20 seconds between each step.

Step 5: Final weight at which the sample tears is noted.

Step 6: Tensile strength is Calculated using:

Tensile Strength Test Apparatus

ObservationspH Residence Time

(Minutes)

Sample Weight (grams)

Acidic 5 1/04-8 341.41

  10 1/04-7 351.89

  15 3/04-2 200.94

  20 1/04-5 271.53

       

Basic 5 26/03-4 331.2

  10 3/04-4 160.9

  15 26/03-2 240.89

  20 26/03-1 131.15

       

Neutral 5 3/04-3 231.59

  10 1/04-3 331.50

  15 1/04-2 406.19

  20 1/04-1 301.69

pH Sample Thickness (mm)

    1 2 3 4 5 Mean

Acidic 1/04-8 0.94 0.9 0.8 0.8 0.74 0.836

  1/04-7 0.66 0.62 0.6 0.64 0.62 0.628

  3/04-2 0.72 0.6 0.48 0.48 0.5 0.556

  1/04-5 0.5 0.52 0.54 0.56 0.42 0.508

               

Basic 26/03-4 0.62 0.6 0.68 0.7 0.62 0.644

  3/04-4 0.9 0.84 0.7 0.78 0.94 0.832

  26/03-2 0.66 0.66 0.7 0.7 0.84 0.712

  26/03-1 0.6 0.52 0.54 0.48 0.58 0.544

               

Neutral 3/04-3 0.6 0.64 0.74 0.68 0.78 0.688

  1/04-3 0.62 0.58 0.66 0.68 0.66 0.64

  1/04-2 0.6 0.52 0.54 0.66 0.58 0.58

  1/04-1 0.6 0.52 0.54 0.62 0.52 0.56

Analysis

4 6 8 10 12 14 16 18 20 220

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Tensile Strength Vs Residence Time (Combined Plot)

Acidic NeutralBasic

Residence Time (mins)

Ten

sile S

tren

gth

(M

Pa)

Stage 1

4 6 8 10 12 14 16 18 20 220

5

10

15

20

25

30

35

40

45

50

Conversion Vs Residence Time (Combined)

Acidic BasicNeutral

Residence Time

% C

on

vers

ion

Final Trial

pH Plasticiser Residence

Time

(Minutes)

Sample Weight

(grams)

Neutral Glycerine 15 16/04-2 456.2

Neutral Sorbitol 15 16/04-3 794.95

Neutral PEG 15 16/04-4 558.11

Plasticiz

er

Sample Thickness (mm)

    1 2 3 4 5 Mean

Glycerin

e

16/04-2 0.68 0.6 0.6 0.8 0.72 0.68

Sorbitol 16/04-3 0.48 0.5 0.5 0.5 0.6 0.516

PEG 16/04-4 1.1 0.94 0.82 0.8 0.7 0.872

Stage 2

Glycerine

Sorbitol

PEG 400

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Tensile Strength for Different Plasticizers

Tensile Strength for Dif-ferent Plasticisers Ten-sile Strength (N/mm^2)

Properties Sorbitol Glycerine PEG

Brittleness Least Flexible Flexible structure Flexible structure

Tensile strength Highest

TS :26.06MPa

14.31MPa 16.14MPa

Glycerine

Sorbitol

PEG

0 5 10 15 20 25 30 35 40 45 50

Conversion For Different Plasticizers

Conversion %

Suggested PPS

Future Scope

Exploring other Sources of Starch

Effect of varying concentrations of Reagents

Extensive Testing

Extraction of Starch from peels

Understanding the effect of Reagents on other

components of the peel

Thank You