2. Polyethylene is classified into several different categories based mostly on its density and branching. These both determine its properties.  Ultra-high-molecular-weight polyethylene (UHMWPE) Ultra-high-molecular-weight polyethylene  Ultra-low-molecular-weight polyethylene (ULMWPE or PE-WAX)  High-molecular-weight polyethylene (HMWPE)  High-density polyethylene (HDPE) High-density polyethylene  High-density cross-linked polyethylene (HDXLPE)  Cross-linked polyethylene (PEX or XLPE)  Medium-density polyethylene (MDPE)  Linear low-density polyethylene (LLDPE)  Low-density polyethylene (LDPE) Low-density polyethylene  Very-low-density polyethylene (VLDPE)  Chlorinated polyethylene (CPE)

4. ● LDPE(Low Density Polyethylene) ▪ Branching▪ Branching (weaker) ▪ Lower tensile strength (deforms easily)tensile strength ▪ Higher ductility (doesn’t break easily)ductility ▪ Molecules are less tightly packed ▪ Cheapest/easiest to make ▪ Application wash bottles Saran & Glad wrap most common = dry-cleaning bags

5. ● HDPE(High Density Polyethylene) ▪ Linear▪ Linear - (stronger) ▪ More tensile strength (doesn’t deform easily)tensile strength ▪ Lower ductility (breaks easily)ductility ▪ More expensive to make ▪ Application Sandwich bags Laundry detergent bottles Grocery bags Pipe

6. ● UHMWPE(Ultra High Molecular Weight Polyethylene) ▪ Extremely long chains  Linear  Very packed  Tough material ▪ Application  Highest impact strength  bulletproof vests  orthopedic implants (artificial hips, knees)  “ice-less” skating rinks

7. PE pipe or fittings are joined to each other by Heat fusion. The principle of heat fusion is to heat two surfaces to a designated temperature, then fuse them together by application of a sufficient force. This force causes the melted materials to flow and mix, thereby resulting in fusion. When fused according to the pipe and/or fitting Manufacturers’ procedures, the joint area becomes as strong as, or stronger than, the pipe itself in both tensile and pressure properties and properly fused joints are absolutely leak proof.

8.  Butt Fusion · Most widely used method for joining individual lengths · Permanent, economical and flow-efficient connection

9.  Saddle/Conventional Fusion · surface of the “saddle” type fitting with concave and convex shaped heating tools

10.  Socket Fusion ·Simultaneously heating both surface