Thermosetting Plastics, Glues, Elastomers and Biodegradable Polymers Flashcards
What is a thermosetting plastic?
A thermosetting plastic has polymer chains which have cross links.
What are the properties of all thermosetting plastics?
They are not remouldable, once set in shape they stay there.
Therefore are not recyclable, however can be choped up and used as fillers in other plastics.
They can be self coloured or be painted post production.
Self finishing.
Do not melt.
Why are thermosetting plastics not sustainable and how long do that take to biodegrade?
They are nearly all oil based.
Take approximately 100+ years to biodegrade.
Give some positives (2) of Urea Formaldehyde and examples of it in use (2). How is it normally molded?
+ Usually white in colour
+ Durable
Plug sockets and electrical fittings
Compression molding
Give some negatives (1) of Phenol Formaldehyde and examples of it in use (1). How is it normally molded?
- Only black in colour
Saucepan handles
Compression molded
Give some positives (3) and some negatives (1) of Melamine Formaldehyde and examples of it in use (1). How is it normally molded?
\+ Can be any colour \+ Hard and Durable \+ Can be very thin (0.5mm) - Relativity expensive Heat resistant surfaces like kitchen work tops. Calandering
Give some positives (3) of Polyester Resin and examples of it in use (2). How is it normally molded?
\+ Only requires small amount of catalyst \+ Very light \+ Very strong Boats and Surfboards Moulded by layering with glass matting.
Give some positives (1) of Epoxy Resin and examples of it in use (1).
+ Glues any non porous surfaces together.
Is a glue called araldite made up of two parts which is mixed and then sets.
Describe compression moulding.
This is the main way of forming thermosetting plastics. The slug of plastic is placed in a “female” mold which also acts as a heater. The former then comes down on the female mould with 5 tonnes of pressure. Creating the object.
Describe Calendaring.
This creates very thin pieces of plastic. The plastic dough or slug is fed into feed rollers which squeeze and stretch the plastic thinner and thinner. The rollers can have patterns and grains on them to imprint on plastic.
Give some positives (1) and some negatives (1) of TPE (Thermo Plastic Elastomer) and examples of it in use (2). How is it normally molded?
TPE is a thermo plastic, elastomer and can be squished and squashed.
+ Squishy so make comfortable handles
- Can’t be clear
Ergonomic overmoulded handles on toothbrushes and electric drills
Overmoulded other product though injection molding
What is LSR (Liquid Silicone Rubber) give examples of it in use (2). How is it normally molded?
LSR is a thermosetting plastic, elastomer and can be squished and squashed.
Used to make baby bottle teats and cookware
What does Bio Batch do?
1% of bio batch can make plastics like LDPE, HDPE, PP, Polystyrenes, PET and even PET completely biodegrable within 1-5 years. Without this it takes 100+ years.
What is PLA? What is it used in?
Also known as Biopol Polylactide, PLA is cellulose based (most abundant organic polymer on earth). It can be used in place of ABS and can be soft like LDPE. It breaks down in six months
Is used in in medical implants, screws, pin and plates, that need to disappear after body has healed.
What is Lactel? What is it used in?
Lactal is a absorbable, water soluble polymer which breaks down in minutes.
Used in tablets and dishwasher capsules.
