Search Results
Isothermal cure characterization of dicyclopentadiene
The glass transition temperature and conversion
Abstract
Conversion (α) and the glass transition temperature (T g) were investigated during the isothermal cure of endo-dicyclopentadiene (DCPD) with a Grubbs catalyst for different temperatures using differential scanning calorimetry. Conversion vs. In (time) data at an arbitrary reference temperature were superposed by horizontal shift and the shift factors were used to calculate an Arrhenius activation energy. Glass transition temperature vs. conversion data fell on a single curve independent of cure temperature, implying that reaction of the norbornene and cyclopentene ring of DCPD proceeds in a sequential fashion. Implications of the isothermal reaction kinetics for self-healing composites are discussed.
transition temperature, and the flexibility of prepared copolymers [ 5 – 7 ]. In addition, the presence of a rigid structure in the polymer skeleton, e.g., bisphenyl or dicyclopentadiene, influences on the improving mechanical elongation and toughness of the
Abstract
The addition of suitable cross-linking agents with norbornene-based monomers has significant effects on the thermal properties of the resulting polymers formed by olefin metathesis. Ethylidene norbornene (ENB) and endo-dicyclopentadiene (endo-DCPD) were mixed separately with various loadings of three different cross-linking agents and then polymerized with the addition of Grubbs’ catalyst. The polymerization kinetics and resulting glass transition temperature (T g) of the systems were evaluated by differential scanning calorimetry (DSC). The addition of the first cross-linking agent, norbornadiene (CL-1), to both endo-DCPD and ENB resulted in decreasing glass transition temperatures with increasing concentrations. In contrast, the addition of the other two cross-linking agents (CL-2 and CL-3), which were both custom synthesized bifunctional norbornyl systems, to both endo-DCPD and ENB resulted in a monotonic increases in T g with cross-linker concentration. By tailoring the loading of these custom cross-linking agents, the properties of these polymer systems can be controlled for various applications, including self-healing composites.
products obtained from these materials was greater than that of similar products prepared from aliphatic-based polymers [ 1 – 4 ]. One of the compounds, which can be widely applied as a comonomer for polymer synthesis is dicyclopentadiene (DCPD) due to
Abstract
The ring-opening metathesis polymerization (ROMP) kinetics of three different norbornene-based monomers, ethylidene norbornene (ENB), endo-dicyclopentadiene (DCPD) and exo-DCPD, in the presence of Grubbs’ catalyst are examined using differential scanning calorimetry and rheokinetic viscosity measurements. Several different parameters were considered, such as, the monomer healing agents (including different monomer mixtures), the catalyst concentration, and test temperature to determine how these parameters influence cure development. The polymerization kinetics, quantified by exothermic peak locations in the case of differential scanning calorimetry and rheokinetic transition times in the case of viscosity measurements, are shown to be highly dependent on monomer type and catalyst concentration. The ENB monomer had the fastest kinetics even at the lowest catalyst concentration compared to the other diene monomers and mixtures.
.12.035 . 9. Ho , TH , Leu , TS , Sun , YM , Shieh , JY 2006 Thermal degradation kinetics and flame retardancy of phosphorus-containing dicyclopentadiene epoxy resins . Polym Degrad Stab 91 : 2347 – 2356 10.1016/j
reaction of unsaturated polyester resin modified by dicyclopentadiene . J Polym Res. 2001 ; 8 : 183 – 90 http://dx.doi.org/10.1007/s10965-006-0149-1 . 4. El-Chahawi M
and mechanical properties of dicyclopentadiene bisphenol dicyanate ester/epoxy co-polymers . Polym Bull 57 : 945 – 952 10.1007/s00289-006-0646-8 . 13. Shimp , DA , Wentworth , JE 1992
characterization of dicyclopentadiene . J Therm Anal Calorim 89 : 453 – 457 10.1007/s10973-006-8467-4 . 15. Kissinger , HE 1957 Reaction kinetics in differential thermal
, GH , Wei , HF , Shiiao , SJ , Kuo , WJ , Sha , YA . Chemical modification of dicyclopentadiene-based epoxy resins to improve compatibility and thermal properties . Polym Degrad Stab 2001 73 : 309 – 318 10.1016/S0141
