Chemistry for Engineers: Biodegradable Plastics

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Questions and Answers

What is the primary role of glycerol in potato starch-based bioplastics?

To help in the breakdown of amylose into glucose units

To serve as a plasticizer that increases flexibility (correct)

To act as a catalyst for polymerization

To enhance the biodegradability of the plastic

Which bacteria species are NOT mentioned as contributors to bioplastics degradation?

Staphylococcus species

Pseudomonas species

Streptococcus species

E. coli (correct)

What characteristic of amylos is primarily responsible for its brittleness in bioplastics?

It is highly branched

It has long-chain polymer structures (correct)

It easily polymerizes with other molecules

It absorbs water effectively

How does adding glycerol enhance the performance of potato starch-based bioplastics?

By absorbing moisture, improving flexibility Signup and view all the answers

What is the function of HCl in the preparation of potato starch-based bioplastics?

To break down amylopectin for film formation Signup and view all the answers

What components make up potato starch?

Amylose and amylopectin Signup and view all the answers

Which of the following factors does NOT contribute to the biodegradation of bioplastics?

Air pressure Signup and view all the answers

What type of plastics break down when exposed to sunlight?

Photodegradable plastics Signup and view all the answers

What is the main reason that water aids in the biodegradation of plastics?

It is a medium for most bacteria and microbes Signup and view all the answers

What added benefit does glycerol provide to starch-based bioplastics other than flexibility?

It promotes moisture retention Signup and view all the answers

What is a primary benefit of bioplastics compared to traditional plastics?

They are made from renewable biomass sources. Signup and view all the answers

Which type of bioplastic is widely used for creating drug capsules?

Starch based Signup and view all the answers

What is a characteristic feature of cellulose-based bioplastics?

They are made from cellulose esters. Signup and view all the answers

Which of the following statements about traditional plastics is true?

They release carbon dioxide when burned, contributing to global warming. Signup and view all the answers

What are starch-based bioplastics primarily made from?

Natural starch Signup and view all the answers

What is one important learning objective for students in the preparation of biodegradable plastics?

To make a plastic film from potato starch. Signup and view all the answers

Which of the following is NOT a use for protein-based bioplastics?

Medical devices Signup and view all the answers

Which of the following materials is commonly utilized for wrapping goods in bioplastics?

Natural starch Signup and view all the answers

What is a significant environmental concern associated with traditional plastics?

They take a long time to decompose. Signup and view all the answers

Which of the following is a characteristic of renewable sources used for bioplastics?

They come from natural plant materials. Signup and view all the answers

Study Notes

Prayer Before Class

Holy Spirit is the true source of light and wisdom
Prayer requests a penetrating mind for understanding
Prayer requests a retentive memory for easy learning
Prayer requests clarity and ease of expression
Prayer requests guidance and success in the work
Prayer is made through Jesus Christ, the Father, and seeks eternal reign

Post-Laboratory Discussion: Preparation of Biodegradable Plastics

The discussion is about biodegradable plastics, specifically, the preparation of them.
It's part of a Chemistry for Engineers Laboratory.

Learning Objective

Students are expected to create a plastic film from potato starch.

PLASTICS

Plastics are derived from petroleum oil.
Plastics rely heavily on scarce fossil fuels.
Burning plastics releases carbon dioxide which contributes to global warming.
Plastics take a long time to decompose.

Decomposition Times of Materials

Batteries: 110 years
Vegetables (leaves, branches): 1-6 months
Food waste: 1 month
Newspapers: > 1 month
Office papers: ~2 years
Wax paper: up to 5 years
Stub filter: 2-3 years
Chewing gum: 30 years
Natural fabrics clothes: 2-3 years
Synthetic clothes: up to 40 years
Shoes (natural): 10 years, (synthetic): 80 years
Iron cans: 10 years
Tin cans: 90 years
Aluminum cans : 500 years
Polyethylene bags and plastic bottles: 100-200 years
Baby diapers: 200-500 years
Rubber tires: 120-140 years
Glass: 1000 years

What are BIOPLASTICS?

Bioplastics are plastics derived from renewable biomass sources, such as vegetable oil or corn starch.

Types of Bioplastics

Starch-based: made from natural starch; used for packaging and drug capsules.
Cellulose-based: made of cellulose esters; used in thermoplastics and packaging.
Protein-based: made from proteins (soy, wheat); used for body panels in automobiles.
Some aliphatic polyesters

Characteristics of Petroleum-based and Bioplastics

Energy consumption: Bioplastics use 48% less energy than petroleum-based plastics.
Raw Materials: Petroleum-based plastics use petroleum, a non-renewable resource. Bioplastics use renewable biomass sources (starch, corn, sugarcane, potato).
Carbon Footprint: Petroleum-based plastics have a high carbon footprint. Bioplastics have a 62% lower carbon footprint than traditional plastics.
Presence of chemicals: Petroleum-based plastics may contain Bisphenol A (BPA). Bioplastics do not contain any toxic chemicals.
Physical properties: Both types are stable, although Bioplastics have high thermo-plasticity.
Biodegradability: Bioplastics can decompose in natural settings in ~180 days. Petroleum-based plastics take > 1000 years to decompose completely.

Biodegradability

Biodegradation is the breakdown of organic materials by natural processes and microorganisms.
Factors that contribute: sunlight, water, bacteria, enzymes, wind abrasion.

Biodegradation of Bioplastics

Biodegradation can be facilitated by bacteria in soil, such as Pseudomonas and Streptococcus species.
Addition of glycerol to potato starch based bioplastics increases the degradation of the bioplastic as it helps the material absorb water.
Water is a medium for most bacteria and microbes.

Degradable Plastics Types

Biodegradable: contain a small percentage of non-oil-based materials like corn starch.
Photodegradable: break down when exposed to sunlight.

Potato Starch

Potato starch is a polymer made of glucose units.
It contains two carbohydrate polymers: amylose (long-chain) and amylopectin (highly-branched), with amylopectin making up the majority.

Potato Starch Based Bioplastic

HCl breaks down amylopectin to enable film formation.
Glycerol acts as a plasticizer, increasing the flexibility and elasticity of the bioplastic.
- Glycerol disrupts hydrogen bonds in the starch, weakening the structure and enabling further plasticity.
- Glycerol increases the bioplastic's ability to absorb moisture further increasing its flexibility.

End of discussion

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Description

Explore the preparation and significance of biodegradable plastics in this Chemistry for Engineers laboratory discussion. Students will learn to create a plastic film from potato starch, while understanding the environmental impact of traditional plastics and the importance of sustainability in materials science.