Fiber-reinforced matrix compositions

Fibers for reinforcing matrix materials, comprising:

• a plurality of individual fiber bodies having an elongated length defined between two opposing ends and comprising at least one synthetic polymer, said individual fiber bodies being substantially free of stress fractures and substantially non-fibrillatable when mechanically agitated within the matrix material to be reinforced, said fiber bodies having a generally quadrilateral cross-sectional profile along said elongated length, thereby having width, thickness, and length dimensions
• wherein the average width is no less than 1.0 mm;
• wherein the average width is no more than 5.0 mm;
• wherein the average thickness is no less than 0.1 mm;
• wherein the average thickness is no more than 0.3 mm;
• wherein the average length is no less than 20 mm;
• wherein the average length is no more than 100 mm;
• wherein the average fiber width to thickness ratio is no less than 5;
• wherein the average fiber width to thickness ratio is no more than 50;
• wherein said fiber bodies have a Young's modulus of elasticity no less than 3 Giga Pascals;
• wherein said fiber bodies have a Young's modulus of elasticity no more than 20 Giga Pascals;
• wherein said fiber bodies have a tensile strength no less than 350 Mega Pascals;
• wherein said fiber bodies have a tensile strength of no more than 1200 Mega Pascals;
• wherein said fiber bodies have a minimum load carrying capacity in tension mode no less than 40 Newtons per fiber body;
• wherein said fiber bodies have a minimum load carrying capacity in tension mode no greater than 900 Newtons per fiber body;
• wherein said fiber bodies have an average square area to volume ratio no less than 7.0 mm—1;
• wherein said fiber bodies have an average square area to volume ratio no more than 22.1 mm—1;
• wherein said fiber bodies have an average bendability “B” no less than 25 mN−1*m−2;
• and
• wherein said fiber bodies have an average bendability “B” no more than 500 mN−1*m−2;
• said bendability “B” of said fibers being determined in accordance with the formula, B=1/(3·E·I), wherein the moment of inertia “I” for a generally rectangular cross-section is computed in accordance with the formula, Irectangle={fraction (1/12)}·w·t3, wherein “w” is the average width and “t” is the average thickness of the generally rectangular cross-section.

Process for manufacturing fibers, comprising:

• melt extruding at least one synthetic polymeric material through a sheet dye;
• cooling the extruded sheet to below ambient temperature;
• cutting the extruded sheet to form separate fibers to achieve a generally quadrilateral cross-sectional provide and resultant average width and thickness dimensions, wherein the average width is at least 1.0 mm, wherein the average width is no more than 5.0 mm, wherein the average thickness is at least 0.1 mm, and wherein the average thickness is no more than 0.3 mm;
• stretching said fibers longitudinally by a factor no less than 10 and no greater than 20;
• and
• cutting said fibers to provide average fiber length no less than 20 and no greater than 100 mm.

Fibers for reinforcing matrix materials, comprising:

• a plurality of individual fiber bodies having an elongated length defined between two opposing ends and comprising at least one synthetic polymer, said individual fiber bodies being substantially free of stress fractures and substantially non-fibrillatable when mechanically agitated within the matrix material to be reinforced, said fiber bodies having a generally quadrilateral cross-sectional profile along said elongated length, thereby having width, thickness, and length dimensions wherein the average width is no less than 1.0 mm;
• wherein the average width is no more than 3.0 mm;
• wherein the average thickness is no less than 0.075 mm;
• wherein the average thickness is no more than 0.15 mm;
• wherein the average length is no less than 20 mm;
• wherein the average length is no more than 60 mm;
• wherein the average fiber width to thickness ratio is no less than 7;
• wherein the average fiber width to thickness ratio is no more than 30;
• wherein said fiber bodies have a Young's modulus of elasticity no less than 4 Giga Pascals;
• wherein said fiber bodies have a Young's modulus of elasticity no more than 20 Giga Pascals;
• wherein said fiber bodies have a tensile strength no less than 400 Mega Pascals;
• wherein said fiber bodies have a tensile strength of no more than 1,600 Mega Pascals;
• wherein said fiber bodies have a minimum load carrying capacity in tension mode no less than 20 Newtons per fiber body;
• wherein said fiber bodies have a minimum load carrying capacity in tension mode no greater than 1,000 Newtons per fiber body;
• wherein said fiber bodies have an average square area to volume ratio no less than 10.5 mm−1;
• wherein said fiber bodies have an average square area to volume ratio no more than 42 mm−1;
• wherein said fiber bodies have an average bendability no less than 150 mN−1*m−2;
• and wherein said fiber bodies have an average bendability no more than 2,500 mN−1*m−2.