SURFACE PHOTOGRAFTING POLYMERIZATION OF STYRENE ON LDPE FILM

ABSTRACT

Styrene (St) was photografted onto LDPE substrates with different methods including a one-step method, pre-irradiation method, and pre-grafting method. Percent conversion (CP) and grafting efficiency (GE) of LDPE/St polymerization systems were measured by the gravimetric method. The results show that the one-step method is not very effective, no matter which photoinitiator (BP, BPO, Irgacure 651 and ITX) is used. The pre-irradiation technology, by which the dormant groups are introduced onto the substrates in advance, is favorable relatively. If the pre-grafting method is employed, AA is the most preferred one among the monomers examined (AA, MA and MAH). In addition, it is found that in the absence of photoinitiators and at lower temperatures (lower than 50°C), no grafted polymer is produced; but at a high temperature (e.g., 80°C), a remarkable amount of grafted polymer of St is formed (GE=44.9%). The phenomena indicate that St is prone to be grafted onto LDPE film by auto-initiation.

Keywords:

• Photografting polymerization
• Styrene
• LDPE film

ACKNOWLEDGMENT

This research has been supported by Special Funds for Major State Research Projects (G1999064800) and the Chinese State Outstanding Youth Foundation (20025415), which are gratefully acknowledged.