24 Questions
What is the temperature range of polylactic acid's melting point?
157 - 170 °C
What is the method of synthesizing polylactic acid through ring-opening polymerization?
With the presence of metal catalysts
What is a property of polylactic acid besides being biodegradable and biocompatible?
Imparting good mechanical properties
Which of the following is NOT an application of polylactic acid?
Production of electronic components
What is the purpose of a sensor?
To detect physical parameters and convert them into electrical signals
What is polylactic acid synthesized from?
Fermented plant starch
What is a possible reinforcement material for polylactic acid?
Carbon fibers
In which fields is polylactic acid widely used?
Biomedical and pharmaceutical fields
What type of molecules are pharmaceuticals, such as diclofenac, often comprised of?
Complex organic molecules
What is the working electrode material used in the electrochemical sensor for detecting diclofenac?
Carbon Paste with MWCNT or Graphene
What is the outcome of the oxidation reaction of diclofenac on the surface of the sensing electrode?
Release of electrons to form radical intermediates
Why is the detection of polycyclic aromatic hydrocarbons (PAHs) important?
Because they are carcinogenic and mutagenic compounds
What is the material used to coat the graphite carbon in the electrochemical sensor for detecting 1-Hydroxypyrene?
PAMAM/Cr-MOF/GO composite
What is the operating voltage range of the electrochemical sensor for detecting 1-Hydroxypyrene?
+0.7 to -0.5V
What is the primary route of exposure to polycyclic aromatic hydrocarbons (PAHs)?
Through respiration and diet
What is the purpose of electrochemical sensors in detecting pharmaceuticals and PAHs?
To monitor their concentration and know their toxic effects
What is the primary method of forming a polymer?
Through covalent bonding
What is the characteristic of Kevlar that makes it resistant to fire and chemical attack?
High chemical stability
What is the definition of a monomer?
A simple molecule with two or more bonding sites
What is the characteristic of Kevlar that makes it suitable for use in tyres and industrial cables?
High impact resistance
What is the process by which Kevlar is synthesized?
Condensation polymerization
What is the characteristic of conducting polymers?
High electrical conductivity
What is the use of Kevlar in clothing?
All of the above
What is the benefit of Kevlar's high crystallinity?
It increases its resistance to high temperature
Study Notes
Biodegradable Polymers
- Biodegradable polymers are materials that deteriorate and completely degrade when exposed to microorganisms, aerobic, and anaerobic processes.
Polylactic Acid
- Can be synthesized by two methods: direct condensation of lactic acid at 200 °C and ring-opening polymerization of lactide in the presence of metal catalysts.
- Properties: • Thermoplastic • Melting temperature: 157 – 170 °C • Good mechanical properties, barrier behavior, and excellent shaping and molding properties • Good optical property • Biodegradable, biocompatible, and compostable • Can reinforce fillers
- Applications: • Widely used in biomedical and pharmaceutical fields due to biocompatibility and bioresorbable properties • Used in controlled drug release, prostheses, sutures, medical implants, and scaffolds for tissue engineering • Can be reinforced with carbon fibers to produce composites of high mechanical strength • Used as a food packaging material
Sensors
- A device that detects a physical parameter of interest (e.g. heat, light, sound) and converts it into an electrical signal.
Polymer Technology
- A polymer is a large molecule made up of small and simple molecules joined together chemically through covalent bonds.
- A monomer is a simple molecule with two or more bonding sites that forms covalent linkages with other monomer molecules to form a macromolecule.
Composite Polymers
- A combination of two or more distinct components to form a new class of material suitable for structural applications.
Kevlar
- Synthesized from 1,4-phenylenediamine and terephthaloyl chloride through condensation polymerization.
- Properties: • Extremely lightweight • Highly crystalline • High impact resistance • High temperature resistance • Resistant to fire and chemical attack • Exhibits high chemical stability • Shows excellent stability over a wide range of temperatures for prolonged periods • Possesses high tensile strength and modulus
- Applications: • Used to make tires, racing sails for boats, and bulletproof vests • Used in industrial cables and brake linings • Used in the construction of aircraft and space vehicles • Used in the manufacturing of gloves, jackets, and other articles of clothing
Conducting Polymers
- An organic polymer with a delocalized pi-electron system, having electrical conductance of the same order as a conductor.
- Examples: Diclofenac detection using a carbon-based sensor.
Working Principle of Conducting Polymers
- Working electrode: Carbon Paste with MWCNT or Graphene
- Counter Electrode: Carbon Paste or Platinum
- Reference Electrode: Ag/AgCl
- Process: Screen Printing Technique on PVC substrate
- Oxidation reaction occurs on the surface of the sensing electrode, releasing electrons to form radical intermediates.
Electrochemical Sensors for Hydrocarbons (1-Hydroxypyrene)
- Working electrode: PAMAM/Cr-MOF/GO(Composite)
- Counter Electrode: Platinum
- Reference Electrode: Ag/AgCl
- Operating Voltage: +0.7 to -0.5V
- Electrochemical sensors are used to detect 1-Hydroxypyrene, a carcinogenic and mutagenic compound.
This quiz covers the definition and characteristics of biodegradable polymers, including their synthesis and properties, with a focus on Polylactic acid.
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