Search results for " MATERIALI"

Modelling of phase transitions and residual thermal stress of CTBN rubber modified epoxy resins during a pultrusion process

2007

Abstract The implicit finite difference and fourth order Runge-Kutta method are used both to solve the heat transfer problem in the pultrusion reaction and to calculate the temperature and conversion distributions within a thermoset composite profile. The aim of our work is to study the influence of a rubbery phase added to the epoxy matrix in production conditions. The results have shown that the rubber modified systems have a low exothermic temperature peak value, so that neither the amount of cured resin nor the final product properties are limited. First of all we will show that the phase transition (gelation and vitrification) zones within the die change as the amount of rubber varies …

Recycling of a starch-based biodegradable polymer

2002

A new starch-based polymeric system, ZI1OU from Novamont, mainly composed of starch and polycaprolactone, was reprocessed several times in an extruder to investigate the recyclability of this biodegradable polymer. A previous investigation of the thermomechanical degradation in a mixer has been also done. The degradation is mostly due to the thermal stress but the presence of the mechanical stress strongly increases the degradation kinetic. During melt processing two concurrent processes take place: the first is the degradation, i.e. the breaking and shortening of polymeric chains, mostly occurring in the PCL phase; the second is the formation of some crosslinked structure in the starch pha…

OPUNTIA FICUS INDICA/MATER-BI® BASED GREEN COMPOSITES FOR FERTILIZER CONTROLLED RELEASE DEVICES PRODUCTION

Drilling characteristics and properties analysis of fiber reinforced polymer composites: A comprehensive review

2023

Fiber-reinforced polymer (FRP) composites play a vital role in the production of structural and semi-structural components for engineering applications. The drilling process is a commonly employed machining process for FRP composites to join the FRP structural elements. Usually, the FRP composites possess a heterogeneous nature because of their multi-layered structure, hybridization, and the presence of multi-phase materials. Hence, common problems like delaminations, fuzzing, buckling, cracking, matrix and fiber burning occur during the drilling operations. These problems cause dimensional inaccuracy, poor surface finish, and tool wear and reduce the mechanical strength of the composites. …

Effect of Short-Term and UV Irradiation Aging on the Behaviour of SBS-Modified Bitumen

2022

To obtain road bitumen with improved temperature and fatigue resistance, polymers and/or rubbers could be added to it. A particularly suitable polymer for bitumen modification is styrene-butadiene-styrene (SBS) copolymer but limited information is available about the ageing behaviour of modified binders. In this work, two neat bitumens, with different penetration grades, and two SBS-modified bitumens, containing different SBS amounts, were selected, and their short-term and UVB ageing behaviour were investigated considering dynamic shear rheometry and Attenuated Total Reflectance-Fourier Transformation InfraRed spectroscopy (ATR-FTIR). Short-time ageing behaviour was investigated performing…

STRUMENTI E MATERIALI PER LA FABBRICAZIONE DIGITALE IN ARCHITETTURA/INSTRUMENTS AND MATERIALS FOR DIGITAL MANUFACTURING IN ARCHITECTURE

2017

Il contributo descrive strumenti e materiali oggi disponibili per la fabbricazione digitale in architettura, offrendo un’ampia panoramica sulle tecniche di stampa 3D e su come potrebbe rivoluzionare le costruzioni con importanti ricadute tecniche, economiche e sociali. Dal concetto di mass customization alla creazione dei Fab Lab, dal Contour Crafting alla tecnologia D- Shape e al progetto WASP assistiamo a un ripensamento del processo architettonico, ma anche a una ricerca sui materiali naturali, ecosostenibili e “programmabili”. The article describes tools and materials available today for digital manufacturing in architecture, offering a wide overview of 3D printing techniques and how it…

PLLA-fibrin scaffolds for Vascular Tissue Engineering

2013

Thermal and rheological characterisation of a thermoset matrix for filament winding modelling

2004

Rheo-kinetic behaviour of an epoxy resin, coupled with an aliphatic polyamines hardener, used in fibre reinforced plastics, was analysed comparing experimental data to theoretical models. Then the modelling of technological filament winding process for thermoset matrix composites, developed through a numerical code realized with MATLAB, is reported. The model includes winding and curing phase decoupling the manufacturing process into sub-models. Four sub-models are used: fibre motion, thermal, kinetic and rheological model. Considerable differences are obtained in process condition, using several thermal treatments. The numerical modelling helps to detect the process conditions to optimise…

PLA based biocomposites reinforced with Posidonia oceanica leaves

2018

Abstract Biocomposites can valorize some natural products related to natural processes or crop and waste industries. In this work, leaves of Posidonia oceanica (PO), dominant sea grass in the Mediterranean Sea, were used to prepare PLA based biocomposites. Materials were prepared by melt mixing PLA with PO as filler. The morphology as well as the mechanical and thermal properties of PLA/PO composites were evaluated and related with the influence of the content and size of PO. Moreover, the experimental elastic moduli of the biocomposites was modelled employing the Halpin–Tsai (HT) model. Furthermore, in order to take into consideration the high porosity of PO leaves, the HT parameters relat…

Use of Biochar as Filler for Biocomposite Blown Films: Structure-Processing-Properties Relationships

2021

In this work, biocomposite blown films based on poly(butylene adipate-co-terephthalate) (PBAT) as biopolymeric matrix and biochar (BC) as filler were successfully fabricated. The materials were subjected to a film-blowing process after being compounded in a twin-screw extruder. The preliminary investigations conducted on melt-mixed PBAT/BC composites allowed PBAT/BC 5% and PBAT/BC 10% to be identified as the most appropriate formulations to be processed via film blowing. The blown films exhibited mechanical performances adequate for possible application as film for packaging, agricultural, and compost bags. The addition of BC led to an improvement of the elastic modulus, still maintaining h…