CONTROLLED CTE HIGH PERFORMANCE FILMS FOR SPACE STRUCTURES

BTBA IS A THERMOPLASTIC POLYIMIDE EXHIBITING A COMBINATION OF GOOD PROCESSABILITY AND HIGH PERFORMANCE (CHEMICAL RESISTANCE, HIGH MECHANICAL, ADHESIVE, THERMOMECHANICAL, ANDTHERMO-OXIDATIVE PROPERTIES) DUE TO THE PRESENCE OF CRYSTALLIZABLE GROUPS WITHIN THE POLYMER WHICH INTRODUCE SEMICRYSTALLINE CHARACTER THROUGH THERMAL ANNEALING. THE COMBINATION OF THESE QUALITIES OVERCOMES THE SHORTCOMINGS OFMOST COMMERCIALLY AVAILABLE HIGH PERFORMANCE POLYIMIDES. THIS PROGRAM OBJECTIVE IS THE DEVELOPMENT OF FILM PROCESSINGMETHODS TO ORIENT THE SEMICRYSTALLINE THERMOPLASTIC BTBA FILM TO IMPROVE AND CONTROL CTE, FRACTURE TOUGHNESS, THERMOMECHANICAL BEHAVIOR, STRENGTH, AND STIFFNESS. CONTROLLED ORIENTATION OF THE FILM WILL BE PERFORMED BY HOT STRETCHING, SIMULTANEOUS WITH THE INTRODUCTION OF SEMICRYSTALLINE CHARACTER THROUGH THERMAL ANNEALING. THIS WILL PERMIT TAILORING PROPERTIES SUCH AS NEAR-ZERO CTE TO MEET AEROSPACE APPLICATIONS SPECIFICALLY REQUIRING HIGH TEMPERATURE, TOUGH STRUCTURAL FILM AND FILM-BASED COMPOSITESAND RESISTANCE TO MICROCRACKING AND CHANGES IN DIMENSIONAL STABILITY. THIS PROGRAM WILL INVOLVE: 1. THE EVALUATION OF A PROCESS FOR CONTROLLED STRETCHING OF FILM AT ELEVATED TEMPERATURES FOR ORIENTATION AND CONTROL OF SPECIFIC PROPERTIES. 2. CHARACTERIZATION OF THE FILMS, AND 3. IDENTIFICATION OF KEY APPLICATIONS. THE EXTENT TO WHICH THIS IS ACHIEVABLE WILL BE DETERMINED. THE PHASE II EFFORT WILL OPTIMIZE AND INTEGRATE THIS TECHNIQUE WITH BTBA FILM PRODUCTION.