New Methods for Producing Nylon 6,6 Fibers with Enhanced Mechanical Properties

electrospinning;solid state polymerization;nylon;high modulus fiber;polyamide

Jung, Dongwook ; Dr. Richard Kotek, Committee Co-Chair,Jung, Dongwook ; Dr. Richard Kotek ; Committee Co-Chair

University:North Carolina State University

关键词: electrospinning;    solid state polymerization;    nylon;    high modulus fiber;    polyamide;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/5557/etd.pdf?sequence=1&isAllowed=y

美国|英语

来源: null

【 摘 要 】

Aliphatic polyamides are very important thermoplastic polymers. They exhibit good mechanical properties and therefore these polymers are suitable in many industrial applications. To improve mechanical properties of these polymers, a lot of efforts have been made by focusing on orientation and crystallinity. These two important parameters can be improved by increasing draw ratios. However, it is difficult to overcome traditional draw ratios for polyamides due to strong hydrogen bonding between amide linkages in the polymer chains. Many approaches have been done to suppress hydrogen bonding in polyamides. Plasticizers such as ammonia, iodine, salts and several spinning methods such as dry spinning, wet spinning, gel spinning, dry-jet wet spinning have been investigated.More specialized methods for obtaining high modulus aliphatic polyamides such as vibrational zone drawing/annealing as well as laser heating zone drawing/annealing are also discussed. A new technique that involves the dry-jet wet spinning and drawing GaCl3/nylon 66 complex has been developed. This new method allows overcoming traditional draw ratio for nylon 66 by disrupting the interchain hydrogen bonded network.Fibers with a very high modulus and strength were obtained when high molecular weight nylon 66 was used. Solid state polymerization (SSP) of nylon 66 is reported to obtain high molecular weight of nylon 66.It was found the polymerization temperature is the most the most important factor that controls the final molecular weight of the polymer. The kinetic of SSP was also investigated by using various experimental conditions. Low (30,000 g/mole) and high molecular weight (170,000 g/mole) nylon 66 were used to prepare, nano- scale non-woven by using an electrospinning technique. The experiments showed that a mixed solvent consisting of formic acid and chloroform is a good medium for electrospinning nylon 66.Fiber diameter increased and fiber diameter distribution was broader with increasing polymer concentration in both low and high molecular weight nylon 66. Initial modulus of electrospun web improved for high molecular weight nylon 66 particularly when a low polymer concentration of 3% was used.This study demonstrated that the use of high MW nylon 66 is a simple approach for improving the mechanical properties of electrospun filaments.