Biomedical applications of collagen

The colloidal structure of bitumen: Consequences on the rheology and on the mechanisms of bitumen modification

In this article, ultrafine gelatin (Gt) fibers were successfully produced with the use of the electrical spinning or electrospinning technique. A fluorinated alcohol of 2,2,2-trifluoroethanol (TFE) was used as the dissolving solvent. The morphology of the electrospun gelatin fibers was found to be dependent on the alteration of gelatin concentration ranging from 2.5% w/v to 12.5% w/v at 2.5% increment intervals. Based on the electrospun gelatin fibers obtained, 10% w/v gelatin/TFE solution was selected and mixed with 10% w/v poly(epsilon-caprolactone) (PCL) in TFE at a ratio of 50:50 and co-electrospun to produce gelatin/PCL composite membranes. Contact-angle measurement and tensile tests indicated that the gelatin/PCL complex fibrous membrane exhibited improved mechanical properties as well as more favorable wettability than that obtained from either gelatin or PCL alone. The gelatin/PCL fibrous membranes were further investigated as a promising scaffold for bone-marrow stromal cell (BMSC) culture. Scanning electron microscopy (SEM) and laser confocal microscopy observations showed that the cells could not only favorably attach and grow well on the surface of these scaffolds, but were also able to migrate inside the scaffold up to 114 microm within 1 week of culture. These results suggest the potential of using composite gelatin/PCL fibrous scaffolds for engineering three-dimensional tissues.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jbm.b.30128

Electrospinning of gelatin fibers and gelatin/PCL composite fibrous scaffolds.

Current research on the blends of natural and synthetic polymers as new biomaterials: Review

https://www.cell.com/trends/biotechnology/pdf/S0167-7799(03)00211-7.pdf

Polymeric cryogels as promising materials of biotechnological interest.

https://arpi.unipi.it/bitstream/11568/798598/2/polacco%20798598.pdf

A review of the fundamentals of polymer-modified asphalts: Asphalt/polymer interactions and principles of compatibility

The use of polymer modified asphalts for waterproofing and in road pavement has been continually increasing worldwide, because a relatively small quantity of added polymer can significantly enhance performance and durability. The knowledge of the morphological structure of such materials is still incomplete and controversial, mainly because of the compositional complexity. In practice, rheology is one of the most useful tools for the study of polymer modified asphalt. Particularly, nonlinear rheology may give unique information that helps to interpret how the polymer organizes when it is blended with asphalt. In this paper, besides a brief description of linear rheological properties and modeling, particular attention is paid to the most recent studies on the structure and to material functions, such as shear viscosity and relaxation modulus in the nonlinear viscoelastic region. The correlation of nonlinear behavior with polymer characteristics and with the architecture established when polymers are blended with asphalts is then described.

Relation between polymer architecture and nonlinear viscoelastic behavior of modified asphalts

Asphalt modification with different polyethylene-based polymers

Asphalt is known to be a colloidal suspension in which asphaltenes are covered by a stabilizing phase of polar resins and form complex micelles that are dispersed in the oily maltenic phase. In order to enhance its mechanical properties (e.g., in road paving), asphalts are often loaded with polymeric materials, thereby obtaining blends that can have different physical or chemical structures, depending on the composition of the added polymer. Asphalts modified by the addition of reactive ethylene terpolymers were prepared and their dielectric and rheological properties were measured both before and after a cure at high temperature. Even if it is not possible to determine the exact nature of the chemical interactions between asphalt and polymer, master curves obtained from dynamic data clearly show that during the cure the material tends to the behavior of a cross-linked network.

Rheology of asphalts modified with glycidylmethacrylate functionalized polymers

http://eprints.adm.unipi.it/524/1/EUROPOL%2DD%2D08%2D01110%2D1.pdf

Giovanni Polacco

Papers

A review of the fundamentals of polymer-modified asphalts: Asphalt/polymer interactions and principles of compatibility

Relation between polymer architecture and nonlinear viscoelastic behavior of modified asphalts

Asphalt modification with different polyethylene-based polymers

Rheology of asphalts modified with glycidylmethacrylate functionalized polymers

Rheological Properties of Asphalt/SBS/Clay Blends