Polypropylene is known for the ease with which row nuclei are formed when the melt is stretched. Because all the crystals grow in register, this opens possibilities for systematic study which would not otherwise be available
Picture: H.M.White
| A Row Structure in Polypropylene
Polypropylene is known for the ease with which row nuclei are formed when the melt is stretched. Because all the crystals grow in register, this opens possibilities for systematic study which would not otherwise be available Picture: H.M.White |
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| Row Structure growing from a fibre
in Polyethylene
High modulus fibres of polyethylene melt over 10° above the bulk polymer, so it is possible to grow row structures from them. At bottom left is a Tekmilon fibre, from which lamellar crystals grow. These start with the same orientation as the fibre, but daughter crystals develop with their axis systematically rotated with respect to their parent. At top right is much finer banding formed when the specimen is sudenly cooled. Studies of this system by M.I.Abo-el Maaty (now at Mansoura, Egypt) have resolved many long lasting questions about banding in spherulites. Picture: M.I.Abo el-Maaty |
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