High performance fiberglass composition with improved elastic modulus

A glass fiber formed from a composition comprising:

• SiO2 in an amount from 50.0 to 55.6% by weight;
• Al2O3 in an amount from 19.5 to 23.0% by weight;
• CaO in an amount from 1 to 8.5% by weight;
• MgO in an amount from 10.0 to 14.0% by weight;
• Na2O in an amount from 0.0 to 1.0% by weight;
• K2O in an amount from 0.0 to less than 1.0% by weight;
• Li2O in an amount from 0.0 to 4.0% by weight;
• TiO2 in an amount from 0.0 to 2.5% by weight,
• Y2O3 in an amount from 6.0 to 10.0% by weight;
• La2O3 in an amount from 0 to 10.0% by weight;
• Ce2O3 in an amount from 0 to 5.0% by weight;
• and
• Sc2O3 in an amount from 0 to 5.0% by weight, wherein said glass fiber has an elastic modulus between 88 and 115 GPa and a fiberizing temperature of 2,277° F. or less.

A reinforced composite product comprising:

• a polymer matrix;
• and
• a plurality of glass fibers formed from a glass composition comprising:
• SiO2 in an amount from 50.0 to 55.6% by weight;
• Al2O3 in an amount from 19.5 to 23.0% by weight;
• CaO in an amount from 1.0 to 5.0% by weight;
• MgO in an amount from 10.0 to 14.0% by weight;
• Na2O in an amount from 0.0 to 1.0% by weight;
• K2O in an amount from 0.0 to less than 1.0% by weight;
• Li2O in an amount from 1.0 to 4.0% by weight;
• TiO2 in an amount from 0.0 to 2.5% by weight,
• Y2O3 in an amount from 0 to 10.0% by weight;
• La2O3 in an amount from 0 to 10.0% by weight;
• Ce2O3 in an amount from 0 to 5.0% by weight;
• Sc2O3 in an amount from 0 to 5.0% by weight;
• and
• a total concentration of La2O3+Y2O3 in an amount from 2.0 to 10.0% by weight, wherein the glass fibers have an elastic modulus between 88 and 115 GPa, a tensile strength according to ASTM D2343-09 of at least 4,400 MPa, and a fiberizing temperature of 2,277° F. or less.