PBT/PET blends

Blends of PBT with polycarbonates have been widely used for car bumpers. Interest in PBT/PET blends and PBT/ASA has arisen because of the good surface finish possible even with glass-reinforced grades. Copolyesters based on PBT but with some longer chain diol or acid are also now produced. 

After having studied in our laboratory, polymer blends of amorphous polymers poly-c-caprolactone and poly (vinyl chloride) (1,2) (PCL/ PVC), blends with a crystalline component PCL/PVC (3,4), poly(2,6-dimethyl phenylene oxide) (PPO) with isotactic polystyrene (i-PS) (5) and atactic polystyrene (a-PS) with i-PS (6), we have now become involved in the study of a blend in which both polymers crystallize. The system chosen is the poly(1,4-butylene terephthalate)/poly(ethylene terephthalate) (PBT/PET) blend. The crystallization behavior of PBT has been studied extensively in our laboratory (7,8) this polymer has a... 

Figure 2. PBT/PET blends glass-transition temperatures, Tg vs. PET percent as determined by DSC.

Figure 10. Density and apparent degree of crystallinity vs. log time for the 20/80 PBT/PET blend crystallized at 200° (%)y 150° (O), and...

PBT/PET blends are used for making visible parts of both large and small appliances that need the appeal of smooth and glossy surface along with high stiffness, strength, and DTUL. There are also other electrical and automotive applications. Compared to the neat PBT molding resins, the market for the blend is still relatively small. 

Figure 4.147 Flexural modulus vs. temperature for SABIC Innovative Plastics Enduran PBT/PET blend polyester alloy/ blend resins.

PBT/PC blends were commercialized by Dow, Mobay, Bayer, BASF, and GE Plastics with high modulus, heat resistance, tensile and impact strength, solvent resistance, and UV stability. Mobay and Dow commercialized polyethylene terephthalate (PET)/PC blends with solvent resistance, low-temperatnre impact, and tensile strength. PBT/PET blends with good surface appearance were introdnced by GE Plastics. 

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