GLASS

Glass is an amorphous (non-crystalline) solid which is often transparent and has widespread practical, technological, and decorative usage in things like window panes, tableware, and optoelectronics.

RAW MATERIALS

  • sand
  • soda ash
  • limestone and
  • other ingredients, such as iron and carbon which provide colour

Another important ingredient in the glass manufacturing process is cullet or recovered glass, obtained from recycling centres and bottle banks.

Raw Materials

BATCHING

Raw materials are stored in large silos, from where they are measured and delivered to batch mixers, according to pre-programmed recipes. batch houses use leading-edge technology to ensure that the mixed material or “batches” delivered to our furnaces meet the stringent quality standards.

Batching

MELTING

The batch is continuously fed into the furnace, which is the beginning of what is known in the glass industry as the “hot end”. And hot it is indeed: the temperature of a furnace is approximately 1 500° C. Operating 24 hours a day, 7 days a week, it is no surprise that a furnace has a limited lifespan, lasting between 8 to 10 years, before requiring a rebuild.

It takes some 24 hours for a batch of raw materials to be converted into molten glass. Red-hot liquid glass is continuously drawn from the furnace through a submerged throat.

From the furnace, the molten glass makes its way to the refiner area, where it is cooled to approximately 1 200° C. Maintaining the correct temperature is extremely important, not just to keep the flow of the molten glass correct, but also because it influences the quality of the end product.

From the refiner, the forehearths deliver glass to the individual bottle-making machines.

The molten glass enters the feeder and flows through cavities in an orifice plate. Streams of glass are cut into gobs of a predetermined weight – exactly as much as is needed to make a single bottle. These gobs are then guided into the individual moulds of the bottle-making equipment, as part of a process known as forming.

Melting

POLYMER

A polymer Is a large molecule, or macromolecule, composed of many repeated subunits. Because of their broad range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life.  Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function. Polymers, both natural and synthetic, are created via polymerization of many small molecules, known asmonomers. Their consequently large molecular mass relative to small molecule compounds produces unique physical properties, includingtoughness, viscoelasticity, and a tendency to form glasses and semicrystalline structures rather than crystals.

 Polymerization  is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks.

Types of Polymers & Its Uses:

1) Polycarbonate: It is a clear plastic used to make shatterproof windows, lightweight eyeglass lenses, and many other items that have lightweight applications. There are two types of polycarbonates, thermoplastic and thermoset. A thermoplastic can be molded in any shape when it is hot whereas a thermoset does not melt, and it cannot be remolded nor recycled. They are used to make things that need to be really strong and heat resistant.

2) Polyethylene: This is probably the polymer that you see and use the most in your day to day routine. Polyethylene is the most popular and widely used plastic in the world. It is used to make items like grocery bags, shampoo bottles, children’s toys, plastic food containers and even bullet proof vests.

3) Polyesters: Polyesters are the polymers, in the form of fibers which are now also made into a fabric. It is used to make normal clothing since polyester is economical. Apart from clothes it is also a plastic, and is often used to make shatterproof bottles that hold your favorite refreshing beverages and drinks.

4) Polystyrene: Polystyrene is an inexpensive and hard plastic commonly used in everyday life. The outside housing of the computer you are using is probably made of polystyrene, as well as the housings of electrical equipment like hairdryers, TVs and kitchen appliances. Model cars and airplanes are made from polystyrene, as well as many other toys. There is also foam packaging and insulation and a lot of molded parts on the inside of your car, like the radio knobs.

PLASTIC

Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organics that are malleable and can bemolded into solid objects of diverse shapes. Plastics are typically organic polymers of high molecular mass, but they often contain other substances.

The world’s first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term ‘plastics’. Many chemists contributed to the materials scienceof plastics, including Nobel laureate Hermann Staudinger who has been called “the father ofpolymer chemistry” and Herman Mark, known as “the father of polymer physics”.

Common plastics and uses

A chair made with a polypropylene seat

  • Polyester (PES) – Fibers, textiles.
  • Polyethylene terephthalate (PET) – Carbonated drinks bottles, peanut butter jars, plastic film, microwavable packaging.
  • Polyethylene (PE) – Wide range of inexpensive uses including supermarket bags, plastic bottles.
  • High-density polyethylene (HDPE) – Detergent bottles, milk jugs, and molded plastic cases.
  • Polyvinyl chloride (PVC) – Plumbing pipes and guttering, shower curtains, window frames, flooring.
  • Polyvinylidene chloride (PVDC) (Saran) – Food packaging.
  • Low-density polyethylene (LDPE) – Outdoor furniture, siding, floor tiles, shower curtains, clamshell packaging.
  • Polypropylene (PP) – Bottle caps, drinking straws, yogurt containers, appliances, car fenders (bumpers), plastic pressure pipe systems.
  • Polystyrene (PS) – Packaging foam/”peanuts”, food containers, plastic tableware, disposable cups, plates, cutlery, CD and cassette boxes.
  • High impact polystyrene (HIPS) -: Refrigerator liners, food packaging, vending cups.
  • Polyamides (PA) (Nylons) – Fibers, toothbrush bristles, tubing, fishing line, low strength machine parts: under-the-hood car engine parts or gun frames.
  • Acrylonitrile butadiene styrene (ABS) – Electronic equipment cases (e.g., computer monitors, printers, keyboards), drainage pipe.
  • Polyethylene/Acrylonitrile Butadiene Styrene (PE/ABS) – A slippery blend of PE and ABS used in low-duty dry bearings.
  • Polycarbonate (PC) – Compact discs, eyeglasses, riot shields, security windows, traffic lights, lenses.
  • Polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS) – A blend of PC and ABS that creates a stronger plastic. Used in car interior and exterior parts, and mobile phone bodies.
  • Polyurethanes (PU) – Cushioning foams, thermal insulation foams, surface coatings, printing rollers (Currently 6th or 7th most commonly used plastic material, for instance the most commonly used plastic in cars).

Classification

Thermoplastics and thermosetting polymers

There are two types of plastics: thermo-plastics and thermo-setting polymers. Thermoplastics are the plastics that do not undergo chemical change in their composition when heated and can be molded again and again. Examples include polyethylene, polypropylene, polystyrene and polyvinyl chloride. Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are assumed to have infinite molecular weight. These chains are made up of many repeating molecular units, known as repeat units, derived from monomers; each polymer chain will have several thousand repeating units.

Thermosets can melt and take shape once; after they have solidified, they stay solid. In the thermosetting process, a chemical reaction occurs that is irreversible. The vulcanization of rubber is a thermosetting process. Before heating with sulfur, the polyisoprene is a tacky, slightly runny material, but after vulcanization the product is rigid and non-tacky.

THERMO-SETTING PLASTICS

Thermoset Curing Process

Thermoset plastics contain polymers that cross-link together during the curing process to form an irreversible chemical bond. The cross-linking process eliminates the risk of the product remelting when heat is applied, making thermosets ideal for high-heat applications such as electronics and appliances.

Features & Benefits

Thermoset plastics significantly improve the material’s mechanical properties, providing enhances chemical resistance, heat resistance and structural integrity. Thermoset plastics are often used for sealed products due to their resistance to deformation.

Pros

  • More resistant to high temperatures than thermoplastics
  • Highly flexible design
  • Thick to thin wall capabilities
  • Excellent aesthetic appearance
  • High levels of dimensional stability
  • Cost-effective

Cons

  • Cannot be recycled
  • More difficult to surface finish
  • Cannot be remolded or reshaped

THERMO PLASTICS

Thermoplastics Curing Process

Thermoplastics pellets soften when heated and become more fluid as additional heat is applied. The curing process is completely reversible as no chemical bonding takes place. This characteristic allows thermoplastics to be remolded and recycled without negatively affecting the material’s physical properties.

Features & Benefits

There are multiple thermoplastic resins that offer various performance benefits, but most materials commonly offer high strength, shrink-resistance and easy bendability. Depending on the resin, thermoplastics can serve low-stress applications such as plastic bags or high-stress mechanical parts.

Pros

  • Highly recyclable
  • Aesthetically-superior finishes
  • High-impact resistance
  • Remolding/reshaping capabilities
  • Chemical resistant
  • Hard crystalline or rubbery surface options
  • Eco-friendly manufacturing

Cons

  • Generally more expensive than thermoset
  • Can melt if heated

DIFFERENCE BETWEEN MORTAR AND CONCRETE

MORTAR

Mortar is used to hold building materials such as brick or stone together. It is composed of a thick mixture of water, sand, and cement. The water is used to hydrate the cement and hold the mix together. The water to cement ratio is higher in mortar than in concrete in order to form its bonding element. When mixed, it is a much thicker substance than concrete, making it ideal as a glue for building materials like brick.

CEMENT CONCRETE

Like mortar, concrete is a mixture of sand, cement, and water, but it also contains rock chippings or gravel which makes it much stronger and more durable than mortar. Because it needs a low water to cement ratio, it is much thinner when mixed, making it difficult to use as a bonding element. Concrete is used in structural projects and is often reinforced with steel rebar to maintain its structural integrity as the soil beneath it settles. It is best used for support, such as beams, walls, or other building foundations.