Monofilament physical properties

Small amounts of surface damage are found to produce a marked change in the most probable value of the static friction of monofilament contacts. This frictional force or critical junction rupture stress decreases with time often in a linear manner. The rate of change is a function of the normal load and becomes pronounced above a critical load which is about one tenth of the calculated plastic flow stress in normal loading. There is an empirical correlation between this rate of friction change and the extent of microslip detected in the contact prior to the initiation of the rapid slip phase. At a constant normal load the observed rate increases with velocity. It is not yet possible to identify the processes responsible for the type of damage produced in these fibre systems but it has been demonstrated that frictional measurements can provide a very sensitive means of detecting low levels of wear which may ultimately lead to a severe deterioration in physical properties. 

Polymer Number Monofilament Suture Physical Properties Suture In Vivo BSR at One Week ... 

Spandex has better mechanical and physical properties than rubber fiber in terms of tenacity, modulus, anti-aging, linear density, and dye ability. Dry spun spandex has round, oval, or dumbbell shaped filament cross-sections, while wet spun spandex has mainly irregular filament profiles. In some spandex fiber, the filament fusion can be so strong that fibers merge into one another. Melt spun spandex is produced as monofilaments or multifilaments of predominantly round cross-sections and smooth surface. 

A composite material or simply a composite is a duplex and multifunctional material composed of at least two elements working together to produce a structural material with mechanical and physical properties that are greatly enhanced compared to the properties of the components taken separately. In practice, most composites consist of a bulk material called the matrix and a reinforcement material or filler, added primarily to increase the mechanical strength and stiffness of the matrix but also sometimes to modify its thermal conductivity and electrical resistivity. This reinforcement is usually made of fibers (e.g., monofilaments, whiskers) but can also be particulates (i.e., dispersion strengthened and particle reinforced) or even material having a more complex shape (e.g., mesh, ribbon, laminates, etc.). Composites are first classified according to their matrix phase into three major classes ... 

Figure 19.8 Low and high magnification views of a fibrous blend formed in an extruded monofilament consisting of PP and PS. Internal fibers encapsulate fibers so the filament has a novel hierarchical structure that may be associated with physical property enhancements.

Monofilament is usually extruded using a conventional screw extruder of rather small size, through a die consisting of a series of holes. The monofilaments are extruded downward into a tank of water (quench tank) from which they go to pull-rolls to he drawn and oriented. The physical properties of the strands depend on the conditions of extrusion, on the degree of stretching, and on the temperature at which they are stretched. For HDPE, a melt temperature of between 260 and 290 °C is usually best. For LDPE, about 30 °C lower is better. Strength increases with draw ratio and generally levels out at ratios between 9 1 and 12 1. 

Both woven and nonwoven geotextiles are made from four polymeric materials (polyamide, polyester, polyethylene, and polypropylene) and natural materials. Woven geotextiles may be fabricated with monofilament yams, muldfilament yams, or a combination of each. Nonwoven geotextiles are bonded by one of the several methods thermal, mechanical, or chemical. With the many combinations of materials and processes, it is not difficult to see that the physical properties of geotextiles will vary greatiy among products (Yeo, 2008). 

Synthetic monofilament fabrics, because of their ductility and manory, may be flexed repeatedly without work hardening and fatigue. They may be folded or dented with less chance of damage compared with a metal cloth, and they are lighter in weight. Some appfications require the filter medium to have the physical properties of the synthetic monofilament, but with a metallized surface for static electricity dissipation. Accordingly, a metallized polyester monofilament fabric is produced coated with a 2 pm thickness of luckel. 

Combined mono and multifilament fabrics are now available with useful additional characteristics. Thus such a material is used on disc filter segments, which is elastic and so will expand during the blow-back stage to help with cake release. New belt press filters and large automatic filter presses have put tremendous demands on the physical properties of the filter fabrics, which are being met by heavy dense monofilament fabrics. 

Hence, the studies /hich fotm the basis of this report were conducted to determine the effect of incorporating different quantities of glycolyl moieties into the poly(p-dioxanone) chains on the physical and biological properties of drawn monofilaments. 

A new series of high molecular copolymers was prepared typical properties of these polymers are outlined in Table 8.4. Monofilaments product from these polymers were evaluated for their physical and in vivo properties as monofilament sutures. Typical results of such evaluation are summarized in Table 8.4. 

Physical and In Vivo Properties of Typical Monofilament Sutures... 

W. Channuan, J. Siripitayananon, R. Molloy, G.R. Mitchell, Defining the physical structure and properties in novel monofilaments with potential for use as absorbable surgical sutures based on a lactide containing block terpolymer, Polymer 49 (20) (2008) 4433-4445. 

Both blocky and random poly(p-dioxanone-co-c-caprolactone) copol mers were prepared and extruded into monofilaments to study their physical and biological properties (Bezwada, Shalaby, and Erneta, 1991). Random copolymers were prepared by pol)Tnerizing the desired proportions of p-dioxanone and c-caprolactone in a single step process in the presence of an organometallic catah st and an initiator at elevated temperatures as described above for p-dioxanone. 

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