The Mechanical Properties Of Nylon The 1212 Super-toughening And Toughening System And Submicron Phase

From the 1990's, polymer have been playing a more and more important role in our lives. It is often the starting point to offer polymers high-performance. And making polymers with both high-strength and high-toughness is very difficult. This paper, aiming at new domestic type of nylonl212, made a high-performance studywhich can be divided into two systems, with an emphasis on investigating the toughening mechanism of nylon 1212 and the mechanical properties of it's alloy and submicroscopic morphology.1 Nylon 1212/MBS core-shell impact modifier/compatabilizer ternary blend alloy systemNylonl212 belongs to crystallinity polymers. Though its unnotched impact strength is very high, the notch impact strength is very low due to some submicroscopic crystals. So it's very meaningful and practical to unsettle this problem. The mechanical property study on the above blend system shows that, the impact strength increases with the adding of compatabilizer firstly, and then decreases. When the mass proportion of nylon 1212, MBS, compatabilizer is 80:20:6, the impact strength is the highest, with Izod impact strength 436.58 J/m and charpy impact strength 122.57 KJ/m2. Aiming at these phenomena, this paper made theoretical explains from the point of submicroscopic morphology, action between toughening agent and the matrix and JRG theory.2 Study on super toughening nylon 1212 system by sulfonamide composite toughening agentAlthough certain good effect has been obtained by toughening nylon 1212 using core-shell impact modifier, the result is still not satisfactory enough compared with nylon 6. Because the structure of nylon 1212 is not similar to other polyamides-there are relatively long -CH2- chains between adjacent amide radicles, we can increase its toughness from the view of molecular structure. For the first time, this paper chooses little molecular aromatic sulfonamide as the toughening agent for nylon 1212, so that the -NH2 and -OH radicles take the place of hydrogen bonds formed between amide radicles of nylon 1212, destroy hydrogen bonds between macromolecules, improve the softness of nylon molecules and increase its toughness. The mechanical property study on toughened nylon 1212 showed that, the toughness of toughened nylon 1212 improved greatly, with Izod impact strength above 1000 J/m and charpy impact strength above 201.03 KJ/m2. The elongation at break of nylon 1212 has also improved, while the tensile strength did not decrease greatly. The toughening mechanism is that toughening agent destroyed intermolecular hydrogen bonds of nylonl212, increased thesoftness of molecular chain and toughness of the system; and it induced lots of silver streaks and shear bands at the impact action, absorbed much impact energy, so increased the impact strength greatly.Toughened nylon 1212 did not break at the impact action. Observed under SEM, there was only smallish breaches at the nicks and the phenomena of stress blanching; which showed that there were plenty of silver streaks produced and conduced to improve the toughness. At the pulling action, there were obvious thin neck phenomena in toughened nylon 1212. The rupture plain of nylon 1212 untoughened was sleek; while there were lots of parabola tenacious sockets and fuzzing phenomena in toughened nylon 1212, which showed that there were plenty of shear bands produced. All above can demonstrate the changing effects of the toughening agent to nylon 1212.