Ball-milling Promoted Chemical Bonding between Cellulose and Plastics - Ball Milling Towards Green Synthesis: Applications, Projects, Challenges - page 227

3.0

A

2.5

2.0

1.5

1.0

0.5

0.0

0 1 2 3 4 5

BPO (wt%)

100

B

80

60

40

20

0

0 1 2 3 4 5

BPO (wt%)

Figure 9.18 Effects of BPO content on graft degree (A) and yield (B) of the graft
product with MA ¼ 2.0 ( J ) and 5.0 wt% ( & ). The results shown by ( K )
and ( ' ) are from melt mixing (190 1C, 75 rpm, and 15 min) with
MA ¼ 2.0 and 5.0 wt%, respectively.
Reproduced from ref. 26 with permission of John Wiley & Sons.

These results on ball-milling grafting of MA onto i-PP appears to indicate
that the graft yield is the greatest with MA r 1 wt%, beyond which it rather
reduces with increasing amount of MA, but, conversely, with decreasing
amount of BPO. This leads us to consider the relation of the graft yield with
the weight ratio of BPO/MA, a new parameter. All the results given in
Figures 9.17 and 9.18 are re-plotted in this mode in Figure 9.19. Notably, the
graft yield is expressed by a linear relation with the BPO/MA ratio except for
extreme cases that do not satisfy the linearity, regardless of the individual
content of MA or BPO. Of much interest, this linearity holds over the greater
extent of the BPO/MA with decreasing the MA amount; thus the graft yield
reaches 50%, 73%, and 90% at the upper limit of the BPO/MA weight ratio
of 0.40, 0.61, and 0.81, with the initial amounts of MA of 5.0, 2.0, and
r 1.0 wt%, respectively. Furthermore, if such linearity is not satisfied, the
graft products exhibit extremely low MFI values, in some cases smaller than
the original i-PP, with the MA amounts of 2.0 and 5.0 wt% (Figure 9.20). This
indicates that the free radical grafting of MA is forced to terminate and