Ultra-Strong Knits for Personal Protective Equipment

Abstract

This work focused on the development of ultra-strong knitted fabrics for personal protective equipment used for protection against mechanical damages. Such knits have to have enhanced mechanical strength properties, which strongly depend on knitting pattern and structural characteristics. Six variants of weft knitted structures were developed and knitted from ultra-high molecular weight polyethylene and additional elastomeric component. The elastomeric component was used to increase the elasticity and toughness of knits; however, it had a high influence on mechanical properties, as well. The performed mechanical tests allowed us to identify dependence of mechanical properties, such as breaking force and elongation at break and resistance to abrasion, tearing, cutting and puncture, on architecture and structural parameters of the knits. Obtained results demonstrate that elastomeric component has high influence on mechanical properties knits and can change the principal mechanical behaviour of knits.

Flexible Theoretical Calculation of Loop Length and Area Density of Weft-Knitted Structures: Part II

“…In both rib cases, index I = 1, for one-needle-bar loop. After adding the values of indexes to original formulas for the simplification of the calculations, the following expressions are used for the length calculations of one-needle-bar loop in Milano rib (6) and half-Milano rib (7):…”

“…As the knitted fabrics are increasingly used in technical applications, there is a need for fabrics with different structures and accordingly different physical and mechanical properties, which will consequently behave differently as technical textiles in terms of mechanical properties. Floats of different lengths, tucks, and additional yarns used in the knitted structure enable a great variety of functional properties, such as strength, dimensional stability or exceptional stretch, air and water vapour permeability, etc., which are especially important for products used for technical application [6][7][8][9][10][11]. It is very important to have possibility of an objective prediction of these properties during the designing stage.…”

Flexible Theoretical Calculation of Loop Length and Area Density of Weft-Knitted Structures: Part I

“…The aim of theoretical designing of knitted fabrics—having certain a knitting machine and a vision to produce a high-quality, aesthetic and economical knit—is to select yarns of appropriate fibre composition, structure and properties, knitting pattern and theoretically to calculate the loop length and area density of the fabric by mathematical formulas. It is especially important for knitted fabrics that are going to be used for protective garments in order to predict their physical properties and mechanical behaviour during external hazardous factors [ 1 ]. In almost 100 years, many attempts have been made and various models have been proposed by Dalidovich [ 2 ], Pierce [ 3 ], Chamberlain [ 4 ], Doyle [ 5 ], Leaf [ 6 , 7 ], Munden and Postle [ 8 , 9 , 10 ], Čiukas [ 11 , 12 ], Kurbak and others [ 13 , 14 , 15 , 16 ] to obtain relationships between dimensions of weft-knitted fabrics, properties of the constituent yarns as well as variable factors in knitting, and to describe the knitted structure by mathematical formulas in order to predict the structural and physical properties of the knitted fabric before knitting.…”

“…In almost 100 years, many attempts have been made and various models have been proposed by Dalidovich [ 2 ], Pierce [ 3 ], Chamberlain [ 4 ], Doyle [ 5 ], Leaf [ 6 , 7 ], Munden and Postle [ 8 , 9 , 10 ], Čiukas [ 11 , 12 ], Kurbak and others [ 13 , 14 , 15 , 16 ] to obtain relationships between dimensions of weft-knitted fabrics, properties of the constituent yarns as well as variable factors in knitting, and to describe the knitted structure by mathematical formulas in order to predict the structural and physical properties of the knitted fabric before knitting. The physical and mechanical properties of the weft-knitted fabrics, such as breaking characteristics, dimensional stability, air permeability, etc., are highly dependent on the average loop length in the pattern repeat of the fabric, i.e., on the length of the yarn in one unit of knitted structure [ 1 , 17 ]. While yarn properties, such as raw material, spinning system, linear density and twist [ 18 ], and relaxation state [ 19 , 20 ] have significant influence on the geometry of the knitted loop.…”