Untitled Flashcards Set

Fibers

·        are long, thin strands of matter that can be natural or synthetic.

·         hey are often made of polymers, which are substances made of repeating units called monomers.

Polymers

·        substances made of repeating units called monomers.

Natural fibers

·        are found in nature.

·        They come from plants, animals, or minerals.

·        Examples: Cotton, silk, wool, jute, hemp (csw jh)

Synthetic fibers

·        are man-made and are made from chemicals through chemical synthesis.

·         Examples: Polyester, rayon, acrylic, and nylon(pran)

Cellulose

·        polysaccharide of glucose molecules that are linked through beta glycosidic bonds.

·        It is resistant to acids and bases, thus can be used in a variety of applications.

Ø  Plant-derived fibers contain cellulose which is the most abundant form of carbohydrate in the world.

Uses of Cellulose

Used in preparation of the paper

Ø  medium for writing which were introduced as early as 100 BC in China.

Ø  it is also used in record keeping through books and other printed media.

1950s

Ø  Hercules Incorporated has introduced acid-free paper.

Acid free paper

Ø  it is prepared in neutral conditions where its lignin and sulfur content were removed

addition of nanomaterials

Ø  to improve the characteristics of paper such as printability, glossiness, and barrier properties

2016

·        Chinese developers of the first waterproof and fireproof paper.

Plant Fibers (ropes, textiles, components, infrastructures)

Cotton

Ø  most prominent plant fiber used in textile industry and in making paper bills.

Kevlar

Ø  lightweight, high tensile strength, thermal stable, cut-resistant, and highly flexible fiber

Ø  used to make personal armors, combat helmets, ballistic face masks, ballistic vests, and motorcycle safety clothing.

Nylon

Ø  synthetic plastic material that's made from polyamides.

Ø   It's a thermoplastic polymer

Ø  It is used in making ropes, conveyer and seat belts, clothing, and fishnets due to its high tensile strength.

thermoplastic polymer

Ø  which means it can be melted and reshaped into different forms

metal

Ø  any of a class of substances characterized by high electrical and thermal conductivity as well as by malleability, ductility, and high reflectivity of light.

Properties of Metal

• Malleability

• Ductility

• Luster

• Heat conductivity

• Electrical conductivity

• Have high melting point

• Have high boiling point

• Metals are malleable.

Ø  It means they can be hammered into thin sheets.

• Metals are ductile.

Ø  They can be drawn into thin wires.

• Metals are lustrous.

Ø  It means they have a shiny appearance.

• Metals are good conductor of heat and electricity

Uses of Metals

·        making gadgets

·        buildings

·        infrastructure

·        jewelry-making

·        coins

·        vehicles

·        different equipment

Plastics

Ø  group of materials, either synthetic or naturally occurring, that may be shaped when soft and then hardened to retain the given shape.

Ø  are polymers.

Ø  are corrosion-free, highly nonbiodegradable, durable, lightweight, and able to be molded into the desired form, the demand for these materials has been sustained through the year

Two Types of Plastics

Thermoset

Ø  plastic that cannot be remolded when heated.

Thermoplastic

Ø  can be reheated, reshaped, and cooled into a new form or shape.

Polymer ( LDPE, HDPE, PS, PVC)

Low- density polyethylene (LDPE)

Ø  has a soft and general transparent appearance.

Ø  can be recycled and is the easiest to degrade.

Ø  is used to make plastic bags and cling wraps.

High-density polyethylene (HDPE)

Ø  used to make toys, pipes, helmets, and durable food containers

Polystyrene (PS), also known as Styrofoam

Ø  is used in the packaging industry due to its lightweight and excellent shock absorber.

Polyvinyl chloride (PVC)

Ø  is used in making water and other types of pipes

polymer

Ø  large molecule made up of many smaller units called monomers.

Ø  The word polymer comes from the Greek words poly- meaning "many" and mer meaning "part".

Natural polymers

Ø  occur in nature

Ø  are biodegradable and have better biocompatibility

Ø  Silk, wool, DNA, cellulose, and proteins

synthetic polymers

Ø  are created in a lab.

Ø  are more stable and chemically unreactive.

Ø  are made from petroleum oil,

Ø  are created by scientists and engineers

Ø  polyethylene, polyester, teflon, and epoxy

Teflon (polytetrafluoroethylene)

Ø  is a synthetic polymer that is heat resistant, nonreactive, nonstick, and waterproof.

Ø  It is used in coating cookware, wires, and fabrics

Polyurethane (PUR OR PU)

Ø  created by reacting polyols and diisocyanates (in the presence of a catalyst or ultraviolet light.

Ø  it is used to make insulation panels, gaskets, foam seals, durable elastomeric wheels and tires

Rubber

Ø  it is obtained from the sap of the rubber tree (Hevea brasiliensis)

Ø  used as an electrical and thermal insulator in making rubber bands, hoses, fittings, pipes, tires, and many other applications

rubber sap

Ø  formed a highly flexible, resilient, and moldable material.

Charles Goodyear

Ø  was awarded a U.S. Patent for his discovery on June 15, 1884.

Glass

Ø  it is obtained by extracting silica based compounds from sand.

Ø  is transparent

Ø  it is a thermal and electrical insulator

Ø  it is chemically unreactive (inert).

Ø  is capable of blocking middle infrared radiation(thermal radiation)

addition of boron

Ø  as a component of glass increases its thermal stability and makes it a better material for laboratory purposes

Pyrex Glass (1915)

Ø  technology was introduced by Corning

brittleness

Ø  Another property of glass that warrants improvement

Ø  is a material's property of fracturing when stressed, but with little deformation before breaking

Rudolf Seiden

Ø  introduced his innovation called tempered glass

Tempered glass

Ø  type of safety glass that's stronger and more durable than regular glass

Ø   it breaks into small, regular-sized pieces when broken, thus making it suitable for use in the windshield of vehicles and other materials that are used in public areas

Other Types of Glass

Mirrored glass

Ø  used in architectural designs due to its reflective properties.

Obscured glass

Ø   blurs images yet allows transmission of light.

Laminated glass

Ø  composed of several layers for added toughness, mostly used in windshield of vehicles.

Carbon fibers

Ø  are a more lightweight material with glass-like properties that are being explored for further applications.