PLASTIC

Plastics are excellent materials with unique and very useful properties. You can produce just about anything you can imagine using plastics.

Characteristics of Plastics

History Of Plastics:

1. Before Plastics—Age of the Natural Resins

• Rubber—Tough elastic substance (light cream or dark amber
  colored) from the milky juice (sap) of rubber tree
• Ebonite—Hard black rubber; natural rubber + sulfur
• Gutta-Percha—Dark brown substance like natural rubber
• Shellac—dark-brown material from lac insects

2. Bakelite—The First True Synthetic Plastics

• Leo Hendrik Baekeland invented Bakelite from coal
• Bakelite helped make 20th century “The Age of Electricity”

3. Industrialization of Major Plastics

Year	Type of plastics	Note
1872	Celluloid (Hyatt, USA)	Semi-synthetic
1910	Phenolic resin, “Bakelite” (Baekeland, USA)	From coal
1931	Polymethyl methacrylate (PMMA) (Rohm and Haas, Ger-many)	From coal
1935	Polyvinyl chloride (PVC) (IG Farben, Germany)	From coal
1935	Polystyrene (IG Farben, Germany)	From oil
1938	Nylon 6 (IG Farben, Germany)
1939	Nylon 66 (DuPont, USA)	From coal
1939	High-pressure low-density polyethylene (LDPE) (ICI, Eng-land)
1953	Polyethylene terephthalate (PET) (DuPont, USA)
1953	Low-pressure high-density polyethylene (HDPE) (Montecatini, Italy)	Ziegler catalyst
1955	Medium-pressure high-density polyethylene (HDPE) (Phillips, USA)	Phillips catalyst
1957	Low-pressure high-density polyethylene (HDPE) (Hoechst, Germany)	Ziegler catalyst
1959	Polypropylene (Montecatini, Italy)
1977	Linear low-density polyethylene (LLDPE) (UCC, USA)
1991	Metallocene very-low-density polyethylene (VLDPE) (Exxon, USA)	Metallocene cata-lyst

4. Concept of High Molecular Weight Compounds & Polymers

• Herman Staudinger, German chemist, proposed a new theory that several thousands of reactive units bonded together in chains and form giant molecules to make up cellulose and rubber
• In 1920, Staudinger proposed calling such materials: high molecular weight compounds, macromolecules, or polymers.

5. Nylon—The First Tailor-Made Plastics

• 1931 – Fiber 66 was produced, later called Nylon 66 in 1938

DISI ENGINE

In developing the DISI engine, we aimed to cool the interior of the cylinder as much as possible by promoting fuel vaporization and uniform mixing of atomized fuel and air. This produces a high charging efficiency of the air-fuel mixture and a high compression ratio, which results in significant improvements in both torque and fuel efficiency.

Characteristics of the direct injection engine:

• Fuel is injected from a tiny nozzle into a relatively large cylinder, so it has a high latent heat of vaporization, which efficiently cools the air within (in-cylinder cooling effect).

• The air temperature in the cylinder decreases, which means:

• (1) more air may be charged into the combustion chamber, which produces increased torque.

• (2) the engine is less prone to knocking. This contributes to increased torque, and enables a higher compression ratio that also contributes to good fuel efficiency.

In a direct injection engine, however, the fuel skips the waiting period it would have to endure inside a standard engine and instead proceeds straight to the combustion chamber. This allows the fuel to burn more evenly and thoroughly. For the driver, that can translate to better mileage and greater power to the wheels.

In the past, direct injection posed too many technical hurdles to make it worthwhile for mass market gasoline automobiles. But with advances in technology and greater pressure to make cars run more cleanly and efficiently, it looks as if gasoline direct injection — or GDI as it’s referred to in industry lingo — is here to stay. In fact, most of the major car manufacturers make or plan to soon introduce gasoline cars that take advantage of this fuel saving and performance enhancing system.