Virgin terephthalate

Torres, N., Robin, J. J. and Boutevin, B., Study of thermal and mechanical properties of virgin and recycled poly(ethylene terephthalate) before and after injection moulding, Eur. Polym. J., 36, 2075-2080 (2000). 

In an open reaction vessel, potassium hydroxide has been used for PET depolymerization with success. Complete degradation was accomplished in 8 min in 1-butanol, in 4 min in 1-pentanol, and in 7 min in 1-hexanol working at a constant microwave power of 500 W in a scientific apparatus. This method yielded as products (after acidification) terephthalic acid and ethylene glycol of sufficient purity to be reused as monomers for the synthesis of virgin PET (Scheme 3.14). In most cases, similar reactions under conventional heating required up to 8 h at reflux. ... 

For polymers produced by condensation reactions (see Section 2.4), for example polyamides (PA) or poly(ethylene terephthalate) (PET), the plastic waste may be converted back directly to the monomer by hydrolysis. There is much developmental and pilot plant work in this area. The monomers can then be separated and introduced into the virgin feedstock for polymerization in the normal way. There is no way in which, for example, a PA polymerized from chemically recycled monomer will be inferior to virgin material. This is the ideal procedure, but it is applicable in only a few cases to the remainder of the polymer kingdom, the addition polymers (see Section 2.4). 

Post-consumer waste consists of six major polymers polystyrene (PS), low density polyethylene (LDPE), high density polyethylene (HOPE), polypropylene (PP), polyvinyl chloride (PVC) and polyethylene terephthalate (PET). These polymers are incompatible and form separate phases on mixing. Fabricated products made directly from comingled plastics have poor physical properties, and can compete only with treated lumber at a price of roughly 20% of that for the virgin plastics. When freed of hidden and actual subsidies, this form of recycling is believed to have a negative economic value. 

A leading automobile manufacturer switched to the use of recycled poly(ethylene terephthalate) (PET)(from soda botdes) to fabricate components such as grille reinforcements, window frames, engine covers, and trunk carpets. The use of recycled grade of resin as opposed to virgin resin not only reduced the cost of production but also provided a significant (in 1999, 7.5 million pounds) annual market for recycled PET resin. 

Consumption of virgin polyethylene terephthalate (PET) resin in the United States and Canada totaled 5110 million pounds in 2000 [3]. Bottles were by far the largest application (Fig. 4.8). Soft drink bottles continue to be the largest use for PET bottles, but other applications (custom bottles) have been growing at a much faster rate for the past several years. According to EPA estimates, soft drink bottles accounted for 49.4% of all PET packaging in U.S. municipal solid waste in 1998, and 53.2% of all PET containers in municipal solid waste [1]. 

Addition of 1,3,5-benzenetricarboxyhc acid tris(cyclohexylamide) to iPP decreased its activation energy from 370 to 312 kJ/mol. " Also, half time of the crystallization (t,/2) of virgin iPP was larger than that of nucleated iPP and the required cooling rate of virgin iPP to reach the same relative crystallinity was higher than that of nucleated iPP. Nano-CaCOj decreased activation energy of poly(butylene terephthalate) even at very low concentrations. ... 

Petra 140 (Allied Signal) is a 40 percent glass-reinforced polyethylene tereph-thalate from recycled soda bottles. It has a tensile strength of 26,000 psi and a heat-deflection temperature of 225°C at 264 psi. PC23MS-200 (MCR Polymers) contains at least 25 percent recyclate from personal computer compact disks and polyethylene terephthalate beverage bottles. DMDA-1343NT polyethylene (Union Carbide) contains 28 percent color-sorted recyclate and has physical properties similar to those of virgin stock. Encore resins (Hoechst Celanese) are a family of plastics based on 100 percent reclaimed thermoplastics such as acetal, polyester, polyphenylene sulfide, nylon 6/6, and liquid crystal polymer. 

Virgin carbon fibre reinforced polymer Virgin polyethylene terephthalate Wide-angle X-ray scattering Wood-plastic composite(s)... 

Tertiary recycling Waste plastic is used as the feedstock in a process that generates chemicals and fuels. An example of tertiary recycling is the glycolysis of PET into diols and dimethyl terephthalate that can then be used to make virgin PET. 

The Importance and Practicability of Co-Injected, Recycled Poly(ethylene terephthalate)/Virgin Poly(ethylene terephthalate) Containers... 

AIST A process for converting PET (polyethylene terephthalate) into virgin plastic. The scrap PET is first depolymerized by heating with ethylene glycol and a metal salt catalyst. 

Virgin and recycled polyethylene terephthalate (PET) was blended with polyether-imide (PEI) in proportions between 0 and 50 percent PEI content and samples were examined by differential scaiming calorimetry and Fourier transform infrared spectroscopy. All blends were completely miscible, as indicated by a single glass transition temperature which is dependent on blend composition. Crystallisation rates of PET were retarded strongly at 20 percent PEI content and above, but degree of crystallinity was easily determined from a linear correlation between a structural parameter measured spectroscopically and enthalpy of fusion. Trans conformer activation energy measurement confirmed the effects of PEI content on crystallisation of PET. 9 refs. 

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