Study On Radiation-resistance Of Blends Based On Phthalocyanine Lead And Benzoxazine/Phthalonitrile Resin

In this paper, tetra-amino phthalocyanine lead (PbTAP), which was used as modifier of typical mono-functional benzoxazine (P-a), bi-functional benzoxazine (BA-a), and bisphenol A-type phthalonitrile (BAPh) resin, respectively, was synthesized by using 4-nitro phthalonitrile and lead oxide as main raw material. The aim is to modify blend resins of benzoxazines and phthalonitrile by means of the introduction of PbTAP. The structures of the products were confirmed by Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (1H NMR) spectroscopy, respectively. The thermal and mechanical properties of the cured blends were characterized by differential scanning calorimetry (DSC)and thermogravimetric analyzer (TGA) and dynamic thermal mechanical analyzer (DMA).Furthermore, the change regularity of structures, dynamic mechanical properties, and thermal stability of cured blends were analyzed before and after the irradiation of high-energy gamma raysr by using 60Co as radiation source.For PbTAP/benzoxazine (P-a and BA-a) system, oxazine rings were opened at the lower temperature due to the existence of amino groups compared with pure benzoxazines,which can promote the ring-opening of oxazine rings. And the curing reaction temperature of benzoxazine was gradually decreased with the increaseing content of PbTAP. The values of glass transition temperature (Tg) and the char yield (Yc) at 800℃ of the cured samples increase with the increasing amount of PbTAP. When the dosage of PbTAP was increased from 5% to 30%, the Tg and Yc values for poly(P-a/PbTAP) system were 157-186℃ and 36.7%-54.5%, respectively. And these values for BA-a/PbTAP system were 181-223℃ and 28.1%-49.5%, respectively.For BAPh monomer, it is very difficult to cure under the general condition because of the absent of hydrogen proton. By the introduction of PbTAP into BAPh, the polymerization reaction of BAPh can be conducted at the lower temperature. And the curing temperature of BAPh decreased remarkably with the increasing PbTAP content. The samples were completely cured at 260℃. After sample processing, thermal weight loss of resin were 5%and 10% respectively. Both Tg and Yc values increased with the increasing amount of amino phthalocyanines lead. In addition, T5 was between 368-411℃ and T10 was between 412-447℃ and Tg was between 298-349℃ and Yc at 800℃ was among 61.5%-68.3%.The cured samples were placed in gamma ray environment and the radiation dosage was 100 kGy. Then,the above samples were tested by FT-IR, DMA and TGA. The results showed that the samples of benzoxazine/PbTAP and BAPh/PbTAP showed good structural stability,the dynamic mechanical properties, and thermal stability of the polymer, indicating that these kinds of materials have good ability resistance to high energy radiation.