Tensile properties of polyester

The flexural and tensile properties of polyester composites at various fiber volume fractions are listed in Table I. Strength values increase up to a fiber volume fraction of about 40% but then decrease with increased fiber volume fraction. This is caused by the poor wetting and extensive fiber damage which occurs at higher volume fractions because of compaction and close packing of the fibers. The ultimate flexural strain shows a similar trend. The modulus values increase almost linearly with fiber volume fraction. 

The tensile properties of polyester-based thermoplastic polyurethanes were studied as a function of the time of exposure of the plastics to water, methanol, methanol-water, methanol-Isooctane, and methanol-water-lsooctane. The resulting decrease In the tensile properties of the plastics was attributed to reaction of the plastics with water and methanol. As Indicated by the decrease In properties, reaction with methanol Is Initially faster, but the reaction rate with water Increases with time — presumably because of the autocatalytic nature of the reaction. Nuclear magnetic resonance spectroscopy Indicated that the reaction mechanisms with methanol and water were transesterification and hydrolysis, respectively. 

Comparison of tensile properties of polyester and polypropylene fibres (Source-. From Reference 57.)... 

Some typical properties of polyester-glass laminates are given in Table 25.1. From these figures it will be seen that laminates can have very high tensile strengths. On the other hand some laminates made by hand lay-up processes may have mechanical properties not very different from those of thermoplastics such as the polyacetals and unplasticised PVC. 

Important properties of polyesters are the relatively high melting temperatures (= 265°C ), high resistance to weather conditions and sunlight, and moderate tensile strength (Table 12-6). ... 

Table 9.41 Tensile properties of different materials including 40 wt% glass fiber/TS polyester RP...

S.B. Srahim, R.B. Cheikh, Influence of fibre orientation and volume fraction on the tensile properties of unidirectional Alfa-polyester composite. Compos. Sci. Technol. 67(1), 140-147 (2007)... 

Roupakias, C.P., Bikiaris, D.N., and Karayannidis, G.P. (2005) Synthesis, thermal characterization, and tensile properties of alipharomatic polyesters derived from 1,3-propanediol and terephthalic, isophthalic, and 2,6-naphthalenedicarboxylic acid. /. Polym. Set, Part A Polym. Chem., 43, 3998-4011. 

Effect of fiber loading The loss in tensile properties of OPF-polyester composites upon degradation in soil was quantified by. Loss in tensile strength by 8%, 17% and 35% were observed, respectively after exposure of 3,6 and 12 months. Similarly tensile modulus, elongation at break and impact strength also reduced upon soil exposure. A loss of impact strength by 6%, 18% and 43% were observed, respectively after 3, 6 and 12 months. Similarly the tensile stress, tensile modulus and elongation at break decreased from 35.1 MPa, 3.29 GPa and 3.75%, 34.6 MPa, 2.32 MPa and 2.48%, respectively upon soil burial for 12 months [61]. 

Tensile properties of various jute/polyester composites are given in Table 1. 

The SFPT were conducted on universal test system (100 Q Standalone) to determine the inteifadal adhesion characteristics of treated betelnut fiber with the polyester matrix. Figure 2 shows the schematic drawing of the pullout test Further detail on the sample preparation and the test procedure were explained in the past publication done by the author (Nirmal and Yousif, 2009). The loading speed was 1 mm/min. It should be mentioned here that the tensile properties of single betelnut fiber were studied for dry and wet fibers. Under wet conditions, the fibers were soaked in tap water (hardness 120-130 mg/1) for 24 hr and then tested. 

The results obtained in the field of thermoplastic starch in combination with polymers or copolymers of vinyl alcohol with aliphatic polyesters and copolyesters in terms of biodegradation kinetics, mechanical properties and reduced sensitivity to humidity make these materials ready for a real industrial development starting from film and foam applications. The present global market is around 12000 tons/year. Main producers are Novamont with Mater-Bi trade-mark, ENPAC and National Starch. The tensile properties of films made of two Novamont s Mater-Bi grades are reported in Table 3, in comparison to these of low density polyethylene (LDPE). Figs. 6-7 show applications of Mater-Bi starch-based materials now on the market. 

Ft. D. Rozman, L. Musa, A. Azniwati, and A. Rozyanty, Tensile properties of kenaf/unsaturated polyester composites filled with a montmorillonite filler. J. Appl. Polym. Sci. 119,2549 (2011). 

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