Study of Non-Isothermal Crystallization of Polydioxanone and Analysis of Morphological Changes Occurring during Heating and Cooling Processes

نویسندگان

  • Yolanda Márquez
  • Lourdes Franco
  • Pau Turon
  • Juan Carlos Martínez
چکیده

Non-isothermal crystallization kinetics of polydioxanone (PDO), a polymer with well-established applications as bioabsorbable monofilar suture, was investigated by Avrami, Mo, and isoconversional methodologies. Results showed Avrami exponents appearing in a relatively narrow range (i.e., between 3.76 and 2.77), which suggested a three-dimensional spherulitic growth and instantaneous nucleation at high cooling rates. The nucleation mechanism changed to sporadic at low rates, with both crystallization processes being detected in the differential scanning calorimetry (DSC) cooling traces. Formation of crystals was hindered as the material crystallized because of a decrease in the motion of molecular chains. Two secondary nucleation constants were derived from calorimetric data by applying the methodology proposed by Vyazovkin and Sbirrazzuoli through the estimation of effective activation energies. In fact, typical non-isothermal crystallization analysis based on the determination of crystal growth by optical microscopy allowed secondary nucleation constants of 3.07 × 105 K2 and 1.42 × 105 K2 to be estimated. Microstructure of sutures was characterized by a stacking of lamellae perpendicularly oriented to the fiber axis and the presence of interlamellar and interfibrillar amorphous regions. The latter became enhanced during heating treatments due to loss of partial chain orientation and decrease of electronic density. Degradation under various pH media revealed different macroscopic morphologies and even a distinct evolution of lamellar microstructure during subsequent heating treatments.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Study of Non-Isothermal Crystallization Kinetics of Biodegradable Poly(ethylene adipate)/SiO2 Nanocomposites

Poly(ethylene adipte) and poly(ethylene adipate)/silica nanocomposite (PEAd/SiO2) containing 3 wt. % SiO2  were prepared by an in situ method. The examinations on the non-isothermal crystallization kinetic behavior have been conducted by means of differential scanning calorimeter (DSC). The Avrami, Ozawa, and combined Avrami and Ozawa equations were applied to describe the crystallization kinet...

متن کامل

Crystallization Kinetics Study in Al87Ni10La3 Amorphous Alloy

In this study, the crystallization behavior of melt-spun Al87Ni10La3 amorphous phase was investigated by using X-ray diffraction and non-isothermal differential thermal analysis techniques. The results demonstrated that the amorphous phase exhibited two-stage crystallization on heating, i.e., at first step the amorphous phase transforms into α-Al phase and at second step Al11La3 and Al3Ni inter...

متن کامل

Non-isothermal Primary Crystallization Kinetics of the Amorphous Fe85.3B11P3Cu0.7 Alloy

In the present research, the primary crystallization kinetics of the amorphous Fe85.3B11P3Cu0.7 alloy was analyzed using non-isothermal DSC measurements. The average and local activation energies, Ea, were determined by different isokinetic and isoconversional methods. The results obtained for activation energy in this research, show that due to the complexity of the primary crystallization pro...

متن کامل

Effect of heating rate on morphological features of oxidized electrolessnickel–boron coatings

Due to the high hardness and wear resistance, electroless nickel-boron (Ni-B) coatings have found numerous applications. In the present study, the influence of the heating rate on the morphological features of oxidized electroless Ni-B coatings was investigated. The oxidation behavior of electroless coating layers was studied with TGA method under non-isothermal conditions at heating rates 5, 9...

متن کامل

THE KINETIC AND MECHANISM OF CRYSTALLIZATION OF MGGEO3 IN 65GEO2-15PBO-10MGF2-10MGO GLASS SYSTEM

In this study, the crystallization behavior of a 65GeO2-15PbO-10MgF2-10MgO glass (prepared by the conventional melt quenching technique) has been investigated. The microstructure and crystallization behaviors of this glass were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), non-isothermal differential thermal analysis (DTA) and Fourier transform infrared spectr...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2016