Abstract

PET, as a member of the polyester family, is a semi-crystalline and colorless resin, which is lightweight, impact-resistant and recyclable [1]. Meanwhile, due to its excellent mechanical and electric properties, PET can be used in wide range such as packaging, electronic industry et.al. Plastic bottles, making from PET, are used more one million per minute from all over the world [2]. The details about its properties, composition, manufacture processes are shown in this website.

Introduction

Polyethylene terephthalate (PET), has the appearance of solid white pellets. For the chosen sample, it has diameter of approximately 3mm, which can be shown in figure 1. PET can be widely used in the area of packaging, electronic field, clothing and making into sheet. Among these applications, plastic bottle was chosen to be the main application to analysis the manufacturing methods in this website. 

Fig. 1  Appearance of chosen sample-PET provided by Wankai.   

All various usages are due to its chemical and mechanical properties. There are two main ways to fabricate PET, each of them is based on the function groups of monomers. This website will give detail information about PET from its processing route, manufacturing, applications, safety data sheet and property profile.

Literature review

Part 1 History 

PET has been used more than 60 years. In 1941, PET was patented by John Rex Whiinfeld. In late 1950s, it was first used for photographic films, as well as in flexible packaging. Later on, the glass fiber was doped in PET to reinforce its mechanical properties. [1]

Fig 2. chemical structures of related species.

(a) The structure of PET. (b) The structure of MEG. (c) The structure of DMT. (d) The structure of TPA.

Part 2 Chemical composition

PET, which structure is shown in figure 2(a), only contains three elements, which are carbon (C), hydrogen (H) and oxygen (O). [1] To fabricate this material, there are 3 kinds of monomers (shown in figure 2(b) to (d)) necessary to be use. They are terephthalic acid (TPA), ethylene glycol (MEG) and dimethyl terephthalate (DMT).

Part 3 Fabrication

There are two main types to produce PET. One is through trans-esterification reaction, the other is through esterification reaction. [3] Both of them are used now, but in previous because the limited purity of TPA in trans-esterification reaction, only the other method was used.

Part 4 properties and applications

There are several excellent properties of PET. First, it is chemical stable, which is reflect in its high resistance against different chemicals like acids and bases. Second, it has high barrier effect, so it has low permeability to water and oxygen, and maintain the integrity of products. Besides, it is safe and healthy to use. [3]

Figure 3. market selling weight percent of 5 types of packages.

Because PET has excellent chemical and mechanical properties, it can be used in various areas. It can be widely used in the area of packaging and electronic field. To be specific, because it is nontoxic, it is safe and health to contain food. For example, one of the packaging products is the plastic bottles like water bottles and carbon soft drink bottles. Figure 3 shows the weight percent in the market of different types of packages. [4] Besides, because it has high electron resistivity, it can be used in electronic area to produce electrical insulating product like capacitor.

Property profile

Reflection

From this project, we further realized the importance of communication. An effective communication can help us learn from each other, and combine everyone’s useful suggestion to make the poster better. Meanwhile, we learnt how to search information from professional websites, which is necessary for our future paper writing.