Structure-to-Property Relationships in Addition Cured Polymers. II. Resin Tg and Composite Initial Mechanical Properties of Norbornenyl Cured Polyimide Resins.
Abstract
PMR(polymerization of monomeric reactants) methodology was used to prepare thirty different polyimide oligomeric resins. Monomeric composition as well as chain length between sites of crosslinks were varied to examine their effects on glass transition temperature (Tg) of the cured/postcured resins. An almost linear correlation of Tg versus molecular distance between the crosslinks was observed. An attempt was made to correlate Tg with initial mechanical properties (flex ural strength and interlaminar shear strength) of unidirectional graphite fiber composites prepared with these resins. However the scatter in mehcanical strength data prevented obtaining as clear a correlation as was observed for the structural modification/crosslink distance versus Tg. Instead, only a range of composite mechanical properties was obtained at the test temperatures studied (room temperatures studied (room temperature, 288 and 316C). Perhaps more importantly, what did become apparent during the attempted correlation study was (a) that PMR methodology could be used to prepare composites from resins that contain a wide variety of monomer modifications, and (b) that these composites almost invariably provided satisfactory initial mechanical properties as long as the resins selected were melt processable.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1986
- Accession Number
- ADA172257
Entities
People
- William B. Alston
Organizations
- National Aeronautics and Space Administration