Tensile Strength Of Nylon Research Articles

The influence of processing conditions on tensile properties of wholly thermoplastic composites reinforced with nanotubes

AbstractThis paper is concerned with novel wholly thermoplastic composites (WTCs) reinforced with supercritical carbon dioxide‐aided exfoliated multi‐walled carbon nanotubes (MWCNTs) and the enhancement of mechanical properties. The bicomponent in situ injection molded plaques consist of polyamide 6 (PA6) and microfibers of thermotropic liquid crystalline polymer (TLCP) with miss‐matched melting temperature. Multiple mixing histories with MWCNTs and processing temperatures were studied and tested for minimizing matrix thermal degradation and maximizing tensile properties of the multi‐scale WTCs. The optimum in situ injection molding temperature was found at 300°C with melt blending nylon 6 matrix and exfoliated MWCNTs in advance. Exfoliated MWCNTs acted as bridging elements between the TLCP and the nylon 6 matrix, which lead to effective stress transfer from the nylon 6 matrix to the TLCP fibrils. Compared to the WTCs without MWCNTs reinforcement, tensile modulus and tensile strength in longitudinal and latitudinal directions were both improved. Furthermore, with the reinforcement of TLCP and exfoliated MWCNTs, the tensile modulus and tensile strength of nylon 6 were enhanced by 173% and 35% in the fluid flow direction, respectively. These experimental results for 20 wt% TLCP/PA6 were even better than the mechanical properties of 20 wt% carbon fiber (CF)/PA6 reported in the literature.

Synthesis and properties of nylon 6/66/510 used as hot melt adhesives for metal plate with low-surface-energy coating

In this work, nylon 6/66 and nylon 6/66/510 containing 5 ∼ 20 mol % nylon-510 were synthesized to be used as hot melt adhesive for metal plate with low-surface-energy coating. The effects of mole fraction of nylon-510 (Xm) on the thermal and mechanical properties of nylon 6/66/510 were systematically studied. The results demonstrated that: (1) the melting point of the copolyamide decreases and the glass transition temperature decreases when the Xm value increases; (2) the tensile strength of nylon 6/66/510 remains almost unchanged and is almost equal to that of nylon 6/66; (3) the elongation at break of nylon 6/66/510 is significantly higher than that of nylon 6/66. The crystal structure of the copolyamide was also investigated by wide-angle X-ray diffraction (WAXD). The hot-melt adhesives (HMAs) were prepared from nylon 6/66/510, and the adhesive experiments of HMAs to aluminum sheet with low-surface-energy coating were carried out. The results showed that the peeling strength of HMAs based on nylon 6/66/510 reaches a maximum value when Xm = 15 mol %.

나일론 6 섬유의 감량가공 및 특성 연구

Weight loss treatment of a fiber leads an improvement of its handle and drape properties. Hydrolysis of a fiber is commonly known as a method to reduce its weight of 5-40%. Most of the studies on the weight loss treatment are mainly based on polyester fibers and there has been almost no study on the weight reduction of nylon fibers. In this study, however, in order to develop a use of nylon 6 fiber for the industrial applications such as toothbrush, underwear, carpet and more, weight loss treatment of a nylon 6 fiber was carried out. Under various treatment conditions, morphological analysis were done to observe the change in the structure of the surface and analysis. From the observation of formic acid treated nylon 6 fiber, there were many etched and deformed morphologies. Thermal and crystalline properties were analyzed to find the changes in the crystal structure caused by the weight loss treatment. There were little differences in the crystalline properties of nylon 6 fiber by formic acid treatment. Tensile strength of nylon 6 fiber decreases with acid concentration. The FITR peak intensity of the amide bond decreases with formic acid concentration.

Nylon 610/functionalized multiwalled carbon nanotube composite prepared from in‐situ interfacial polymerization

AbstractPristine multiwalled carbon nanotubes (P‐MWNTs) were functionalized with 4‐chlorobenzoic acid via “direct” Friedel‐Crafts acylation in polyphosphoric acid (PPA)/phosphorous pentoxide (P2O5) medium. The resultant 4‐chlorobenzoyl‐functionalized MWNTs (F‐MWNTs) were soluble in chlorinated solvents such as dichloromethane, chloroform, and carbon tetrachloride. A large scale of nylon 610/F‐MWNT composite could be conveniently prepared by in situ interfacial polymerization of 1, 6‐hexamethylenediamine (HMDA) in an aqueous phase, and sebacoyl chloride with F‐MWNTs in an organic phase. Similarly, nylon 610/P‐MWNT composite was also prepared for comparison. The state of F‐MWNTs dispersion in nylon 610 matrix was distinctively better than that of P‐MWNTs, which could be clearly discerned by both naked eye and scanning electron microcopy (SEM). As a result, the tensile strength of nylon 610/F‐MWNT composite was 4.9‐fold higher than that of nylon 610/P‐MWNT composite. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6041–6050, 2008

TENSILE STRENGTH OF SURGICAL KNOTS IN ABDOMINAL WOUND CLOSURE*

Abdominal wound dehiscence is a surgical catastrophe that can be attributed to patients or technical factors. The technical properties of the monofilament sutures and knots that are commonly used in abdominal closure are poorly understood. The aim of this study was to compare the tensile strength of monofilament sutures tied with conventional knots. To do this, the knot-holding capacity of four types of knots (square, surgeons', Aberdeen and loop) were tested using three types of gauge 1 monofilament suture, namely nylon, polyglyconate and polydioxanone, using a tensiometer. We found that the knot-holding capacity of the loop knot was between twofold and threefold greater than all the other knots examined. In comparing suture types, polyglyconate had the highest knot-holding capacity for all the knots that were examined and there was no difference in the tensile strength of nylon and polyglyconate tied in a square, surgeons' or Aberdeen knot (P < 0.05). In conclusion, our findings suggest that closure of an abdominal wound would be best commenced with a loop knot, using gauge 1 polyglyconate and finished with either an Aberdeen square or surgeons' knot would be appropriate.

Vibration welding of nylon 6 to nylon 66

AbstractVibration welding of dissimilar nylons is a promising technique for assembling complex components made of different polymers. The effects of pressure and meltdown on the tensile strength of nylon 6 (PA 6) to nylon 66 (PA 66) vibration welds were determined in this study using an experimental design and three weld geometries. Weld strengths were generally improved by increasing meltdown and decreasing weld pressure. The weld strength was also shown to vary with the position of the lower melting material for T‐welds. Using differential scanning calorimentry and fracture surface analyses, it is concluded that for all geometries, higher weld strengths can be achieved when both materials are melted. Polym. Eng. Sci. 44:760–771, 2004. © 2004 Society of Plastics Engineers.

Mechanical properties of blends of nylon 6 with a chemically modified polyolefin

AbstractBoth tensile and impact properties were measured of a heterogeneous polymer blend system, consisting of nylon 6 and a chemically modified polyolefin, DuPont CXA3095, which is an ethylene‐based multifunctional polymer. It was found, from the tensile testing, that the blends exhibited no signs of necking, and the addition of a soft resin (CXA3095) reduced the modulus and the tensile strength of nylon 6, whereas the percent elongation at break went through a minimum. When 20 wt % of CXA3095 was added to nylon 6, the impact strength was increased approximately three times. When the factors describing the interfacial adhesion were incorporated, the existing models for predicting the tensile modulus of blends were found to describe the experimental data rather well. In order to help explain the mechanical behavior observed, photomicrographs were taken of the fracture surfaces, using a scanning electron microscope.

Effect of folding on the strength of kevlar 29 and nylon parachute materials

Abstract The effect of folding on the tensile strength of nylon 6,6 and Kevlar 29 parachute materials was investigated. Instrumentation of a packed Kevlar parachute indicated a maximum pressure of 207 kPa on the folds. After 1 year storage the maximum pressure decreased to less than 70 kPa. Samples from the packed parachute showed no loss in strength after 1 year packed storage or after an additional 2·5 years in a loosely packed condition. Results from laboratory tests of folded nylon and Kevlar with 90 kPa pressure on the folds indicated no strength change relative to unfolded control samples for times of up to 3·5 years. Kevlar fabrics exposed for short periods at pressures up to 40 MPa showed a slight decrease in strength with increasing pressure. However, no cases of strength degradation have been observed at low fold pressures typical of those observed in a packed parachute, even at elevated temperatures where thermal ageing of the material occured.

Study of the effect of regrinding on the cumulative damage to the mechanical properties of fiber-reinforced nylon 66

An experimental study of the tensile strength of nylon 66 regrind, with and without short-fiber reinforcement, is reported. For nylon 66 without reinforcement, a uniform increase in tensile strength has been observed with increasing number of moldings. This is due to a further condensation reaction which occurs during molding. For short fiber-reinforced nylon 66 composite, the tensile strength decreases with increasing number of moldings, which is attributed to the cumulative breakage of fiber length through mechanical working. A model based on fiber length analysis is proposed, and the semiempirical equation can be used to predict experimental results and balance cost–end use properties.