Tensile properties weight

Tensile Properties. Tensile properties of nylon-6 and nylon-6,6 yams shown in Table 1 are a function of polymer molecular weight, fiber spinning speed, quenching rate, and draw ratio. The degree of crystallinity and crystal and amorphous orientation obtained by modifying elements of the melt-spinning process have been related to the tenacity of nylon fiber (23,27). 

Definitions of the commonly measured tensile properties are as follows Unear density (tex) is the weight in grams of 1000 m of yam. Tenacity is the tensile stress at break and is expressed in force-per-unit linear density of unstrained specimen, N /tex. Knot tenacity is the tensile stress required to mpture a single strand of yam with an overhand knot tied in the segment of sample between the testing clamps. It is expressed as force-per-unit linear density and is an approximate measure of the britdeness of the yam. Toop tenacity is the tensile stress required to mpture yam when one strand of yam is looped through... 

Table 9. Tensile properties of PPS composites. All the fiber fractions are in weight percents. Data on Specimens a and b arc taken from. Modem Plastic Encyclopedia 96, Mid-Nov 1995 Issue.

The extent of deterioration may be measured by one or more of the following methods visual examination, change in weight, change in tensile properties. Visual inspection was depended upon primarily in the A-5 tests... 

Supply is related to cost. If basic materials become scarce, changes will follow. Thus constraints in the petroleum supply may affect the polymer industry, which is based almost entirely on petrochemicals. We can look for expanded use of paper-based materials to provide factors such as bulk, tensile properties, and thermal resistance combined with the low weights of proper barrier materials. Composites will continue to grow in quantity and complexity. 

Table 7.1 The effect of particulate fillers on tensile properties of poly(ethylene) (filler concentration 25 parts/lOO of polymer by weight)...

More definitive evidence of enzymatic attack was obtained with 1 1 copolymers of e-caprolactone and 6-valerolactone crosslinked with varying amounts of a dilactone (98,99). The use of a 1 1 mixture of comonomers suppressed crystallization and, together with the crosslinks, resulted in a low-modulus elastomer. Under in vitro conditions, random hydrolytic chain cleavage, measured by the change in tensile properties, occurred throughout the bulk of the samples at a rate comparable to that experienced by the other polyesters no weight loss was observed. However, when these elastomers were implanted in rabbits, the bulk hydrolytic process was accompanied by very rapid surface erosion. Weight loss was continuous, confined to the... 

Among the main molecular structural variables in EPDMs that are stipulated by catalyst systems and that affect the vulcanizate tensile properties we may mention molecular weight (MW) and MWD, degree of unsaturation (LG=C 1) and its distribution in the polymer, composition (C S) and monomer sequence length distribution along molecular chains, and long-chain branching if present. Effect of... 

Even though the first report about the synthesis of crystallizable ABC triblock copolymers was published in 1978 for PS-fo-PB-fo-PCL copolymers [114], in that work only a preliminary study of the tensile properties was performed, without considering the crystallizability of the materials. It was only 20 years later, when the preparation of these materials was reconsidered and optimized, that triblock copolymers with relatively narrow molecular weight distributions were obtained [115], a requisite which is indispensable for the generation of well-defined morphologies. To illustrate the complexity and richness of semicrystalline ABC triblock copolymers, PS-fc-PB-fc-PCL triblock copolymers have been chosen. These copolymers have been prepared with a wide composition range (with PCL contents from 11 to 77%) and they have been compared with PS-fc-PCL and PB-fo-PCL diblock copolymers [29,98, 115-118]. 

Using dlethylene glycol (DEG) as an initiator, a copolymer (IV) of PDO/glycolide at 90/10 by weight was preapred and its properties are compared with those of a 90/10 copolymer (II) made in the presence of l-dodecanol (Table IV). Although the tensile properties of IV are comparable those of II, the percent BSR of the latter is higher. This may be associated with a difference in the copolymeric... 

Stars with 32% PSt, (PSt/15-h-PIB/34)g-C8, showed -26 MPa tensile stress. There was no appreciable difference in the tensile properties of unextracted and MEK extracted star blocks [see (PSt/15-h-PIB/34)g-C8 and (PSt/16-h-PIB/34)g-C8]. The modulus and Shore A hardness were slightly higher for the unextracted star, (PSt/16-h-PIB/34)g-C8, which maybe due to the presence of PSt contamination which acts as a rigid filler. A dramatic difference in the tensile behavior was observed when PSt content was increased. Stars with low PIB block molecular weight and high PSt content (46%), e.g., (PSt/21-h-PIB/25)g-C8, showed plasticlike behavior, i.e., it showed a high modulus, a yield point, and a short draw. Ex-... 

The improvements in uniaxial tensile properties which can be achieved through higher molecular weight prepolymers clearly must be balanced against the deleterious effect that the higher prepolymer viscosity exerts on the propellant processing characteristics. 

Table IX. Uniaxial Tensile Properties of Propellants Prepared with Blends of High Molecular Weight and Production CTPB...

It is important to note that tensile strength is controlled by density, of course, but tensile strength is otherwise a molecular phenomenon. Molecular weight, cross-linking, and other chemistiy level factors affect tensile properties. We should note that, with the exception of composites, the polyurethanes we will design based... 

This process has a high catalyst activity of 1,200 kgmol h-1. It produces UHMWPE with improved tensile properties and impact resistance. The molecular weight is greater than 4.5 M Dalton and the polydispersity is less than 3. In contrast, the unsupported catalyst has an activity of only 600 kg mol h-1, however large molecular weights are reached as well. 

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