General treatment of the thermogravimetry of polymers

Abstract

(Au gus t 1] , 1966)Theoreti ca l equ a ti o ns ar e de ve lo pe d for typi cal decompositions of polyme rs including th ose in whi c h the vola tilization does not folJ ow a simpl e "re action orde r" a nd those made up of a composite of seve ral reac tions of diffe rin g e ne rgies of ac tivation. The e ffects of orde r, activation ene rgy, heatin g ra te and te mpe ra ture de pe nd e nce upon th e calc ulated th ermogram s is illu strated. The lite rature on th ermogravim e tri c kine ti cs is c riti cally re vi ewed and coalesced into a logi cal and cohere nt de velopme nt stressin g the inte rrelation of me th ods a nd e mplo yin g a co ns iste nt sys te m of nota tion . As a res ult , a nu mbe r of impro ved me th ods and ne w me thod s for the a nalys is of kineti c data a ppli ca ble to th e co mpl e x sys te ms me nti oned a bove are developed . It is co nc lu de d th at me thods involvin g a va riabl e rate of hea tin g or invo lving seve ra l the rm ogra vime tri c traces at d iffe re nt ra tes of hea tin g a re capa bl e of es tabli s hing th e unique ness of kine ti c pa ra me te rs. A ne w me th od of de te rminjn g init ial pa ra me te rs from rate·conve rs ion data is de veloped . A novel co nce pt is e mpl oyed of programmin g reac ti on va ri a bles (i n thi s case, th e heatin g ra te) in a ma nne r whi c h great ly simplifies th e mathe mati cs of the kin e ti c s'ys te m and whic h shows pro mise of a wide ra nge of a pp lj ca bilit y in th e area of rate processes. Ke y Word s : Degrad a tion, no ni sothe rm al kine ti cs, polyme rs, pyrolys is, th e rm a l deco mp os iti o n, th e rmogra vim e try, th e rm olys is, sta bilit y of po lyme rs.

Evaluation of Exothermic Reactions from Bulk-Vitrification Melter Feeds Containing Cellulose

“…We used 1) Kissinger's (1957) method and 2) the similar Ozawa (1965) and Flynn and Wall (1966) methods, each of which uses varying heating rates β and the reaction peak's maxima.…”

“…The activation energy -E a may be determined from the slope of a plot of ln(β/ T p 2 ) versus 1/T p . Ozawa (1965) and Flynn and Wall (1966) use the relationship:…”

Investigations on Chemical, Thermal Decomposition Behavior, Kinetics, Reaction Mechanism and Thermodynamic Properties of Aged TATB

“…Flynn, Wall [16] and Ozawa [17] proposed a method for calculating kinetic parameters using Doyle's approximation of a temperature integral. It is based on the assumption that thereaction rate depends on the temperature at a constant conversion.…”

Miscibility influence in the thermal stability and kinetic parameters of poly (3-hydroxybutyrate)/poly (ethylene terephthalate) sulphonated blends

“…In order to compare the result of Vyazovkin's method, activation energy may be evaluated by Flynn-Wall-Ozawa method [23,24] . As like as Vyazovkin's method the Flynn-Wall-Ozawa's method involve multiple heating rates (β) and can be used without the knowledge of the kinetic model, the Flynn-Wall-Ozawa's method gives the Equation 7:…”

“…The basic assumption of these methods is that the reaction rate for a constant extent of conversion depends only on the temperature [22][23][24][25] . An advantage of these methods is that the activation energy can be determined as a function of the conversion.…”