BIODEGRADABLE POLYMERS

PARAS KUMAR

M-4 122114803609

UTENSILS MADE OF BIODEGRADABLE PLASTIC

INTRODUCTION

increase in interest in biodegradable materials in recent years. particularly, biodegradable polymer materials (known as biocomposites)

researchers are trying to modify traditional materials to make them user-friendly, environment friendly.

Biodegradable polymers will reduce pollution and produce positive effect environmentally and economically.

designed to degrade upon disposal by the action of living organisms.

can be used in areas such as biomedical areas, tissue engineering and controlled drug delivery

POLYMER MATERIAL SELECTION

various criteria for selection of materials for polymers

for biomedical areas: remains strong till purpose is complete. does not produce toxic effect, is metabolized in body should be processable as a product & can be sterilized easily

• for mechanical degradation various factors considered are: monomer selection initiator selection process conditions and presence of additives

• these factors affect the degradation of polymers

• biodegradation can be accomplished by synthesizing polymers with hydrolytically unstable linkages in the backbone.

PROCESSING

can be processed by conventional means such as compression an injection moulding

moisture must be excluded processing temperature should be managed to stop the reverse

formation of monomer

DEGRADATION

polymers should maintain mechanical properties until no longer needed

occurs in two stages: water penetrates bulk faces, attacks chemical bond,

makes them water soluble, this causes reduction in moleculae wt. but with same properties.

surface erosion occurs when rate of water penetrating

the polymer is less than its conversion in water soluble

materials.

APPLICATIONS

in the biomedical area degradtion of polymeric implants means

that there is no need of a second surgery • In tissue engineering, these can be used to create a scaffold of

tissue which can withstand stress, promote cell growth and which can degrade easily.

• In surgical sutures to hold body tissues together after an accidents.

SOME EXAMPLES

Poly(caprolactone) (PCL) undergoes a two stage degradation process. The first stage is bulk hydrolysis. Lower molecular weight fragments are subject to intracellular degradation. These polymers are studied for drug delivery.

Poly(glycolic acid) (PGA) -Used to make biodegradable drug matrices and sutures for cataract surgery and for repairing inguinal hernias.

Poly (l-lactic acid) (P l-LA) This polymer has been widely used in

sutures, implants and controlled release systems. It’s low molecular

weights are for drug matrices, but its high molecular weights are for osteosynthesis (pins for bone repair).