polymers

polymers

1. special properties of polymers

   • an artificial hip replaces ball and socket of a worn hip join. The socket is made of the polymer Teflon.
     • its surface has almost no friction, so the ball of titanium alloy swivels freely.
       • it is non-toxic and invert (non-reactive), essential inside the body.
         • it can withstand high temperatures.

2. uses of polymers

   • chemists choose monomers that give polymers (plastics) with the properties required for a particular purpose:
     • packing materials must be strong, light and flexible.
       • waterproofing for a tent fabrics must repel water.
         • dental polymers for crowns and denatured are designed to harden when exposed ultraviolet light.

3. disposing of polymers

   • reasons for recycle
     • most polymers are produced from non-renewable crude oil they are no0t biodegradable (microorganisms can not break them down).take up space in waste dumps and land fill sites.
       • polymers can be recycled.
         • its becoming cheaper to recycle polymers than throw them away.
     • to make them biodegradable, polymers are mixed with cellulose or starch that microorganisms will break down.
       • polymers can be burned to generate heat energy.

4. cracking

   • new molecules from crude oil
     • many of the hydrocarbons