TY - JOUR
T1 - Synthesis and characterization of siloxane-containing poly(urea oxamide) segmented copolymers
AU - Buckwalter, Daniel J.
AU - Zhang, Mingqiang
AU - Inglefield, David L.
AU - Moore, Robert B.
AU - Long, Timothy E.
N1 - Funding Information:
This material is based upon work supported in part by the US Army Research Office under Grant W911NF-07-1-0452 Ionic Liquids in Electro-Active Devices (ILEAD) MURI. This material is partially based upon work supported by the National Science Foundation under Grant No. DMR-0923107 . Thanks to Wacker Chemie for supplying the 12K PDMS oligomers and Bayer for supplying the HMDI. Thanks also to Amanda Hudson for her help in acquiring the variable temperature FTIR spectroscopy data.
PY - 2013/8/16
Y1 - 2013/8/16
N2 - An unprecedented family of segmented polydimethylsiloxane poly(urea oxamide) (PDMS-UOx) copolymers displayed thermoplastic elastomeric behavior with improved thermomechanical properties compared to PDMS polyurea (PDMS-U) analogs. A two-step, PDMS end-capping sequence using diethyl oxalate and hydrazine generated difunctional oxamic hydrazide capped oligomers. Polymerization with HMDI provided high molecular weight copolymers, which yielded elastomeric films with monodisperse hard segments. Dynamic mechanical analysis (DMA) of PDMS-UOx copolymers revealed a broad, rubbery plateau that extended for >180 C. The PDMS-UOx service window extended ∼120 C further than a PDMS-U analog, presumably due to enhanced hydrogen bonding and concomitant microphase separation. DSC and WAXD elucidated the amorphous morphology of PDMS-UOx, and DMA, SAXS, and AFM confirmed a well-defined microphase-separated morphology. Incorporation of urea oxamide groups significantly affected microphase separation and thermomechanical properties, and these copolymers offer impact in adhesive and biomedical technologies due to low temperature reaction conditions for unique hydrogen bond containing segmented copolymers.
AB - An unprecedented family of segmented polydimethylsiloxane poly(urea oxamide) (PDMS-UOx) copolymers displayed thermoplastic elastomeric behavior with improved thermomechanical properties compared to PDMS polyurea (PDMS-U) analogs. A two-step, PDMS end-capping sequence using diethyl oxalate and hydrazine generated difunctional oxamic hydrazide capped oligomers. Polymerization with HMDI provided high molecular weight copolymers, which yielded elastomeric films with monodisperse hard segments. Dynamic mechanical analysis (DMA) of PDMS-UOx copolymers revealed a broad, rubbery plateau that extended for >180 C. The PDMS-UOx service window extended ∼120 C further than a PDMS-U analog, presumably due to enhanced hydrogen bonding and concomitant microphase separation. DSC and WAXD elucidated the amorphous morphology of PDMS-UOx, and DMA, SAXS, and AFM confirmed a well-defined microphase-separated morphology. Incorporation of urea oxamide groups significantly affected microphase separation and thermomechanical properties, and these copolymers offer impact in adhesive and biomedical technologies due to low temperature reaction conditions for unique hydrogen bond containing segmented copolymers.
KW - Hydrogen bonding
KW - Polyurea
KW - Thermoplastic elastomer
UR - http://www.scopus.com/inward/record.url?scp=84881558556&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84881558556&partnerID=8YFLogxK
U2 - 10.1016/j.polymer.2013.07.025
DO - 10.1016/j.polymer.2013.07.025
M3 - Article
AN - SCOPUS:84881558556
SN - 0032-3861
VL - 54
SP - 4849
EP - 4857
JO - Polymer
JF - Polymer
IS - 18
ER -