Prof Joana Curto
University of Beira Interior, Portugal
Title: Recycling of silicon coated paper and design of new cellulose based materials
Biography
Biography: Prof Joana Curto
Abstract
An innovative green chemistry approach is used to recycle silicon coated paper and obtain cellulose based materials with industrial applications. The silicon coated paper is used in labeling industry and constitutes a challenge for recycling due to the stability of the siloxane covalent bonding to the OH cellulose ending groups. The silicon coated paper has been successfully processed using a combination of mechanical and chemical processes to obtain recycled cellulose fibers. From this process two types of cellulose fibrous materials were made and tested, depending on their properties, a fibrous pulp material to be integrated in the paper recycling industry and an cellulose based material to be used in civil engineering applications. The coating made from silicone based polymers proved to be very stable and the evaluation of the modifications induced by different combination of unit operation was done using techniques such as scanning electron microscopy, optical microscopy, x-ray dispersive spectroscopy, Fourier transformed infrared attenuated total reflectance spectroscopy and contact angle. The recycled cellulose fibers were used to produce recycled paper, and tensile strength and optical properties were quantified using ISO standards. The recycled pulps were compared with reference Eucalyptus globulus fibers. Using an optimized combination of mechanical and chemical process operations the recycled cellulose fibers obtained presented good mechanical strength with tensile index values for recycled paper of 39,6 Nm/g, in the same range of virgin eucalyptus paper, presenting 42,2 Nm/g. The recycled fibers integration in the paper industry also depends on the paper structure ability to drain water. These step of the formation of paper, because involves an high energy consume, is considered a key process parameter, and has been evaluated by using the Schopper Riegler degree method. The results indicate that 80% of the fibers originating from the recycling process present acceptable values for drainage. The remaining material was processed to be used as a biopolymer material in engineering applications. The results indicate that this material can be molded, its porosity optimized, and different applications can be designed, departing from these recycled cellulose natural fibers.