Crystallization of polymers
Degree of crystallinity
Table:
Polymer	D	ρc	ρa

Nylon (PA66 and PA6)	35–45	1.24	1.08

Polyoxymethylene (POM)	70–80	1.54	1.28

Polyethylene terephthalate (PET)	30–40	1.50	1.33

Polybutylene terephthalate (PBT)	40–50	–	–

Polytetrafluoroethylene (PTFE)	60–80	2.35	2.00

isotactic polypropylene	70–80	0.95	0.85

atactic polypropylene	~0	–	–

High-density polyethylene	70–80	1.0	0.85

Low-density polyethylene	45–55	1.0	0.85

Studying the table that covers 'Crystallization of polymers' in the 'Degree of crystallinity' section, compose one sentence describing only the highlighted cells and provide it inside the JSON object {"answer": "YOUR ANSWER"}.