Gamma-Irradiated EVA-Grafted Copolymers

Grafted EVA copolymers were synthesized using a gamma-irradiation induced grafting method. To accomplish this, a sequence was followed. Initially, distinct mass ratios of EVA and BuA, as outlined in Table 2, were dissolved in 20 ml of toluene. Following this, the prepared solution samples underwent irradiation using gamma rays from a ⁶⁰Co Indian irradiation facility gamma ray at a dose rate of 0.866 kGy/h (the establishment of this irradiation facility was overseen by the National Center for Radiation Research and Technology (NCRRT), a division of the Egyptian Atomic Energy Authority (EAEA)), the irradiation procedure was conducted under atmospheric conditions and at room temperature. The polymers resulting from the process were then precipitated using an excess amount of methanol, subjected to filtration, and finally dried under reduced pressure^{33 (link),35 (link)–37 (link)}.
Table 2

Different formulations of EVA-grafted polymer.

Sample number	EVA (gm)	Butyl acrylate (gm)	Dose (kGy)	Sample code
1	1	–	0	(EVA)0kGy
2	1	–	50	(EVA)50kGy
3	1	1	50	(1EVA:1BuA)50kGy
4	1	2	50	(1EVA:2BuA)50kGy
5	1	3	50	(1EVA:3BuA)50kGy

During the irradiation of the initial reaction mixture, two processes occur simultaneously: graft copolymerization of BuA monomer onto EVA and Homopolymerization of Butyl acrylate (BuA) monomer resulting in the formation of poly butyl acrylate p(BuA) Homopolymer. To separate the grafted copolymer from the homopolymer, a solubilization-precipitation method was employed. The dried precipitated polymers, which included grafted EVA and the non-grafted p(BuA) Homopolymer, were dissolved in toluene and then precipitated in acetone. This caused the Non-grafted p(BuA) Homopolymer to dissolve while the grafted EVA copolymer precipitated as shown in Fig. 2. The resulting material was filtered and dried under reduced pressure until a constant weight was achieved. Key parameters for evaluating the graft polymerization, such as grafting percentage (G%), grafting efficiency (GE%), and the degree of Non-grafted p(BuA) formation (H_{Non-grafted p(BuA)}%), were determined gravimetrically.Figure 2

Preparation stages and separation of EVA-g-p(BuA).