Study On The Preparation And Properties Of Polyplefin-g-N,N-Diallylmelamine And Fibers

As the most widely used thermoplastic polymer materials at present, the applications of polyolefin, particularly polypropylene and polyethylene, are restricted to some extent due to nonpolar and semicrystallization. Polar or functional lateral groups can be grafted onto nonpolar molecular chains of polyolefin via reactive extrusion, enduing it with special functions and making it applicable for more extensive fields. Meanwhile, melt-blown spinning and blended spinning are two important methods to prepare micro/nano fibers, which can be employed to applications of functional polyolefin.In this paper, on the basis of present researches on the applications of functional polyolefin both in China and abroad, with melt-blown polypropylene (PP), low density polyethylene (LDPE) and isotactic polypropylene (iPP) selected as the representative polyolefin, and N,N-Diallylmelamine as the functional monomer, the grafting modification of polyolefin via reactive extrusion was taken on a twin-screw extruder. Consequently, melt-blown polypropylene grafted N,N-Diallylmelamine (PP-g-NDAM), low density polyethylene grafted N,N-Diallylmelamine (LDPE-g-NDAM), and isotactic polypropylene grafted N,N-Diallylmelamine (iPP-g-NDAM) were obtained. On the basis of previous study, PP-g-NDAM melt-blown fibers were prepared via melt-blown spinning, cellulose acetate butyrate (CAB)/LDPE-g-NDAM and CAB/iPP-g-NDAM binary hybrids melt extruded, obtaining corresponding nano-fibers via blended spinning.In the study of PP-g-NDAM, the FTIR spectra illustrate that NDAM was successfully grafted onto PP backbone. The grafting degree (GD) of PP-g-NDAM increased firstly, then decreased with the increase of dicumyl peroxide (DCP) concentration, whereas the GD increased fast originally and then increased gently with the increase of NDAM concentration. However, the melt flow index (MFI) of PP-g-NDAM decreased originally, and then increased with increasing DCP concentration, and decreased slightly with the increase of NDAM concentration. Meanwhile, the degradation of PP was restrained and the thermal stability of PP-g-NDAM was improved after using the antioxygen Irganox1010/Irgafosl68 blends. No crystal tranformation occurred in PP-g-NDAM, as compared with PP, while its melting temperature (Tm) decreased slightly, crystallization temperature (Tc) increased obviously, and thermal stability was enhanced. The PP-g-NDAM melt-blown fibers prepared with the best weight ratio of raw material had an average diameter of 3.1μm. The elongation at break of obtained melt-blown fibers decreased, the air permeability was improved. The active chlorine content was 380μg/g PP-g-NDAM melt-blown fibers at the maximum, and PP-g-NDAM melt-blown fibers had excellent rechargeability of chlorine bleaching.In the study of LDPE-g-NDAM, the FTIR spectra showed NDAM was successfully grafted on the backbone of LDPE. The GD of LDPE-g-NDAM increased firstly then decreased as the BPO concentration increased, and increased as the NDAM concentration increased. However, MFI of LDPE-g-NDAM decreased as the BPO concentration increased, and increased slightly as the NDAM concentration increased. Meanwhile, the crosslinking reaction of LDPE was restrained under using the liquid paraffin and oleic acid. Compared with LDPE, Tm of LDPE-g-NDAM decreased slightly, Tc increased, and thermal stability changed little. The LDPE-g-NDAM nano-fibers, which were prepared via blended spinning, had an average diameter of 486nm. The active chlorine content was 350μg/g LDPE-g-NDAM nano-fibers at the maximum, and LDPE-g-NDAM nano-fibers had excellent rechargeability of chlorine bleaching.In the study of iPP-g-NDAM, the FTIR spectra showed NDAM was successfully grafted onto iPP backbone. The GD of iPP-g-NDAM increased as the DCP concentration increased, and increased as the NDAM concentration increased. However, MFI of iPP-g-NDAM increased as the DCP concentration increased, and increased slowly as the NDAM concentration increased. Compared with iPP, no crystal tranformation occurred in PP-g-NDAM, its Tm decreased slightly, Tc increased obviously, and thermal stability was enhanced. The iPP-g-NDAM nanofibers, which were prepared via combined spinning, had an average diameter of 317nm. The active chlorine content was 700μg/g iPP-g-NDAM nanofibers at the maximum, and iPP-g-NDAM nano-fibers had excellent rechargeability of chlorine bleaching.