Cork is a natural, renewable, sustainable raw material that has been used for many centuries. As a result of this very long term interest, the scientific literature on cork is extensive. The present review focuses on the chemical composition, physical and mechanical properties of cork and on its products and sub-products. The substantial efforts to fully characterise cork, as well as new developments and evolving research, are reviewed, beginning with its histology, growth and morphology (at macro-and microscales). The chemical structure is analysed in detail, covering both the materials that form the wall structure and the low molecular weight, extractable components. The unique properties of cork are discussed and correlated with current knowledge on morphology and chemical structure. Finally, the important industrial applications of cork are reviewed, in the context of research to provide cork with novel, high added-value applications.

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The crystallisation and spherulitic morphology of poly(p‐dioxanone) (PPDX), a thermoplastic polyester‐ether used for medical applications have been studied. Polarised Optical Microscopy (PM) revealed that isothermally crystallised PPDX exhibits large double banded spherulites with a mean banding spacing that increases as the crystallisation temperature increases. The lack of resolution of optical microscopy prevents the double banding from being clearly observed at crystallisation temperatures below 75°C. The spherulitic morphology changed somewhat as a function of crystallisation temperature from well developed structures with a very clear Maltese cross to spherulites with a more granular texture. A Regime III to Regime II transition in growth was detected according to the Lauritzen and Hoffman analysis of spherulitic growth rate data even though there were no apparent major morphological changes in spherulitic structure as crystallisation temperature was varied apart from that described above. The equilibrium melting point was determined using the Hoffman‐Weeks extrapolation procedure and found to be 127°C. Avrami theory was applied to calorimetric overall crystalline conversion data and good fits were obtained with exponents ranging from 3 to 4 as isothermal crystallisation temperature was increased from 50 to 100°C indicating a change from instantaneous to sporadic spherulitic nucleation that was consistent with PM observations. PPDX exhibited a marked tendency to undergo partial fusion and recrystallisation during DSC heating scans. Self‐nucleation results evidenced the existence of the usual three self‐nucleation domains depending on the self‐nucleation temperature (Ts) employed. Additionally, the complex behaviour upon cooling from Ts and subsequent melting was studied in detail.

We have studied the hydrolytic degradation of high molecular weight poly(p-dioxanone), PPDX, sutures. The samples were degraded either in distilled water or in a phosphate buffer at 37 degrees C, and the starting viscosity-average molecular weight was 130 kg/mol. The hydrolytic degradation of PPDX occurs in an approximate two stage process where the amorphous regions of the sample are attacked faster than the crystalline regions of the sample. The changes experienced by the samples as degradation proceeded were successfully monitored by viscosimetry, differential scanning calorimetry (DSC), weight loss, pH changes, and scanning electron microscopy (SEM). Polarized optical microscopy (POM) observations performed on PPDX films revealed that PPDX crystallizes in spherulites whose detailed morphology depends on the supercooling employed during isothermal crystallization. Changes in the spherulitic morphology as molecular weight is reduced are only pronounced when the molecular weight is equal or lower than 8 kg/mol. The dependence of lamellar thickness as a function of isothermal crystallization temperature was examined by atomic force microscopy (AFM) in thin films of PPDX together with melting point data obtained by DSC. Through the use of the Thomson-Gibbs equation, we obtained a value of 166 erg/cm2 for the fold surface free energy of PPDX. This value is in the same range as those obtained previously for similar linear polyesters. The lamellar thickness, as well as the melting point, was found to have a small decreasing dependence with the molecular weight of the samples.