Abstract: The present invention concerns a pre-mix for a syntactic phenolic foam composition; a syntactic phenolic foam composition; and a process for preparing the syntactic phenolic foam composition. The pre-mix comprises thermally expandable and/or expanded thermoplastic microspheres, the microspheres comprising a thermoplastic polymer shell made of a homopolymer or copolymer of 100 to 25, for example 93 to 40, parts by weight of a nitrile-containing, ethylenically unsaturated monomer, or a mixture thereof; and 0 to 75, for example 7 to 60, parts by weight of a non-nitrile-containing, ethylenically unsaturated monomer, or a mixture thereof; and a propellant, or a mixture thereof, trapped within the thermoplastic polymer shell; and one of either a highly reactive phenolic resole resin capable of fully crosslinking at temperatures between 15° C. and 60° C.

Abstract: The present invention concerns a pre-mix for a syntactic phenolic foam composition; a syntactic phenolic foam composition; and a process for preparing the syntactic phenolic foam composition. The pre-mix comprises thermally expandable and/or expanded thermoplastic microspheres, the microspheres comprising a thermoplastic polymer shell made of a homopolymer or copolymer of 100 to 25, for example 93 to 40, parts by weight of a nitrile-containing, ethylenically unsaturated monomer, or a mixture thereof; and 0 to 75, for example 7 to 60, parts by weight of a non-nitrile-containing, ethylenically unsaturated monomer, or a mixture thereof; and a propellant, or a mixture thereof, trapped within the thermoplastic polymer shell; and one of either a highly reactive phenolic resole resin capable of fully crosslinking at temperatures between 15° C. and 60° C.