Thermodynamic properties of polylactones

Abstract

Temperature dependences of isochoric heat capacity, temperatures and enthalpies of physical transitions for polyglycolide, polyw-propiolactone), poly(y-butyrolactone), poly(bvaler0lactone), poly(8-caprolactone), polyundecanolactone, polytridecanolactone, and polypentadecanolactone were studied between 13,8 and (340 -550) K in a vacuum adiabatic calorimeter within a limit of experimental error of about 0,2%. From the results obtained the functions @ ( T ) -H o ( 0 ) , So(T), and G o ( T ) -@(O) were calculated over the range 0 to (340-550) K. Zero entropy of glassy polymers, S:(O), and difference in zero enthalpies of glassy and crystalline states, q ( 0 ) -q ( O ) , were estimated also. Regularities of changes in thermodynamic properties of polylactones, in dependence of the number of atomic groups in a repeating unit, were found that made it possible to evaluate the properties of some polylactones the corresponding experimental data of which are not known. 0025-1 16)3/84/$03.00 AS:(. = 100) AC:(a = 100) K kJ.mol-'

Poly[(4‐hydroxybutyric acid)‐alt‐(glycolic acid)]: Synthesis by Thermal Polycondensation of Metal Salts of 4‐Chlorobutyric Acid Carboxymethyl Ester

“…This feature improves the polymer flexibility and avoids the high rigidity of polyglycolide (T g ¼ 41 8C. [32] ). 2) A double melting peak, which is usually attributed to a recrystallization process that affects the proportion between populations of crystals with a different lamellar thickness, [33] can be observed depending on the crystallization conditions (i.e., second heating run of a hot crystallized sample).…”

Induction time approach to surface induced crystallization in polyethylene/poly (ɛ-caprolactone) melt

“…3 the value of Kg was found to be 8.11 x 104 K 2 in excellent agreement with the work of Phillips et al who reported a value of 8.00x 104 K 2 for a fraction of similar molecular weight. From the following data taken from the literature [24,25] (Ahf = 1.7 x 10 9 ergcm -3, T ~ --342 K, and bo=0.411 nm), ~c~ e was calculated to be 680 erg2cm -4. The necessity of taking the transport term Aq~/kT into account is made clear in Fig.…”

“…In the treatment of the data, the following expression was chosen for the transport term [16]: Aq~/kT = U*/R(T -T~) where U*= 1500 calmol 1 and Too = Tg -30. Tg is the glass transition temperature and was taken as 209 K [24]. From Fig.…”

Controlled ring-opening polymerization of -pentadecalactone with yttrium isopropoxide as an initiator

“…It is well documented that large-membered lactones have little ring-strain and consequently are extremely difficult to polymerize by non-enzymatic methods. Several investigators have reported on polyesters derived from macrolactones [8][9][10][11] , but in all cases, no detailed description of the polymerization was given. Just recently, it was demonstrated clearly that 12 and 13-membered lactones could undergo ring-opening polymerization using an alkali metal methoxide as initiator 12) .…”