Aaron Padilla & Betsy Robb, Plastic Fantastic? walk-through video Information Gallery 1 What is plastic? ![]() Plastic is any synthetic or semi-synthetic organic polymer. While plastics may be made from just about any organic polymer, most industrial plastic is made from petrochemicals. Thermoplastics and thermosetting polymers are the two types of plastic. There are two types of plastics: thermoplastics and thermosetting polymers. Thermoplastics are the plastics that do not undergo chemical change in their composition when heated and can be molded again and again. Thermosets can melt and take shape once; after they have solidified, they stay solid. Amazing Facts about plastic Is plastic safe? video and website Examples of Plasticspolyethylene terephthalate - PET or PETEhigh-density polyethylene - HDPE polyvinyl chloride - PVC polypropylene - PP polystyrene - PS low-density polyethylene - LDPE Gallery 3 Artists who use plastic and Lecture - Mark Manuel from Pacific Islands Marine Debris Program NOAA talk video Information from Kohukua Foundation: Commitment Card, Marine Debris Lesson, Educators Resources, Program Overview, Tips to go plastic free Dealing with Different PlasticsAlthough most of the discarded plastic finds its way into
landfills, about 16% is combusted to produce energy [2]. Since plastic
is derived from petroleum products, its energy yield is almost as high
as fuel oil; plastic yields 19,900 BTU/lb whereas oil yields 20,900
BTU/lb [3]. However, the incineration of plastics produces air pollution
by releasing chemicals such as hydrogen chloride, dioxin and fine
particulate matter [2]. Another way of dealing with plastics is
recycling, but this only accounts for about 7% of the plastics
encountered in municipal solid waste centers [1]. Because plastics pose a
threat to human and wildlife health when disposed of in landfills or
through incineration, engineers are working to increase recycling rates
by improving current recycling technologies while also developing
biodegradable polymers for future use.
A plastic is made up of individual molecules called
monomers, which are linked together to form long chains called polymers.
Each polymer has unique chemical properties, physical properties, and
functions [4]. Consumer plastics are largely made from six different
polymer resins, which are indicated by a number etched onto the surface.
The numbers or resin codes are numbered from 1 to 7. Fig. 2 outlines
the different polymer resins, their resin codes, main properties,
general applications, and potential recycled products. The chemical
composition and function of each resin controls where the resin can be
recycled and the recycling rate [1]. According to the EPA, plastic with
resin code 7 (mixed plastic or other less-commonly used polymers)
accounts for 22% of total plastic waste, but is the least recycled with a
rate of 6%. This could be attributed to the difficulty of separating
mixed plastic during the recycling process. On the other hand, PET, or
resin code 1, only accounts for 12% of the total plastic waste, but has a
recycling rate of about 20% [1]. Because of its widespread use in
drinking bottles, PET is very identifiable and easy to sort. |