Case: Polymers are large molecules formed by the combination of smaller units called monomers. The process of polymerization can occur in two main ways: addition polymerization and condensation polymerization. In addition polymerization, the monomers add to each other without the loss of any atom or molecule, while in condensation polymerization, two monomers join together with the elimination of a small molecule, often water. Polymers like polyethylene and polypropylene are formed through addition polymerization, whereas polymers like nylon-6,6 and polyester are formed by condensation polymerization. The structure and properties of the polymer depend on the type of polymerization, the nature of the monomers, and the reaction conditions.
Questions:
Which of the following is an example of a polymer formed by addition polymerization?
In condensation polymerization, which of the following is eliminated as a by-product?
Which of the following polymers is formed by the polymerization of a single monomer?
Which of the following is an example of a condensation polymer?
Case: Polymers are classified into two categories: thermoplastic and thermosetting polymers. Thermoplastics are polymers that can be melted and re-molded into different shapes, and they are not chemically cross-linked. Examples include polyethylene (used in plastic bags) and polystyrene (used in disposable cups). On the other hand, thermosetting polymers are polymers that, once set, cannot be re-melted and re-molded due to the presence of cross-links between the polymer chains. Examples include Bakelite (used in electrical insulators) and epoxy resins (used in adhesives).
Questions:
Which of the following is an example of a thermoplastic polymer?
Which of the following polymers is a thermosetting polymer?
Thermoplastic polymers can be easily molded or shaped because they:
Which of the following properties is characteristic of thermosetting polymers?
Case: With increasing environmental concerns over plastic waste, biodegradable polymers have gained significance in recent years. These polymers break down into simpler compounds over time due to microbial action or environmental factors. Examples of biodegradable polymers include polylactic acid (PLA) and polyhydroxyalkanoates (PHA). PLA is derived from renewable resources like corn starch and is used in biodegradable plastics. PHAs are produced by bacteria and can be used in medical and agricultural applications. Biodegradable polymers provide a solution to reduce the impact of plastic pollution.
Questions:
Which of the following is an example of a biodegradable polymer?
Polylactic acid (PLA) is obtained from:
The main advantage of biodegradable polymers over conventional plastics is:
Which of the following is NOT a property of biodegradable polymers?
Case: Copolymers are polymers made from two or more different types of monomers. They are classified into three main types: random copolymers, block copolymers, and alternating copolymers. Random copolymers have monomers arranged randomly, while block copolymers have large segments or blocks of one monomer repeated in the chain. Alternating copolymers alternate between two different monomers. Copolymers are designed to combine the properties of different monomers, resulting in materials with enhanced or specific properties. An example is Buna-S, a styrene-butadiene copolymer, used in the production of synthetic rubber.
Questions:
Which of the following is an example of a copolymer used in the production of synthetic rubber?
Which of the following is a characteristic of block copolymers?
Random copolymers:
Which of the following is true about copolymers?
Case: Polymers play a crucial role in the medical field, where they are used in a variety of applications, from drug delivery to prosthetics. Biocompatible polymers like poly(lactic acid) (PLA) and poly(glycolic acid) (PGA) are used to make sutures, surgical implants, and drug-delivery systems. These polymers can degrade over time, eliminating the need for surgical removal. Another example is the use of polyethylene in joint replacement implants due to its high wear resistance and biocompatibility. The use of biodegradable polymers ensures that medical devices can be safely absorbed or broken down by the body without long-term harmful effects.
Questions:
Which of the following is used in the preparation of biodegradable sutures?
Which property of polyethylene makes it suitable for joint replacement implants?
Biodegradable polymers are advantageous in medical applications because:
Poly(glycolic acid) (PGA) is used in medical applications because: