25 research outputs found
Effect of Hemp Shive Sizes on Mechanical Properties of Lightweight Fibrous Composites
AbstractIn this paper, the impact of mean size of anisometric hemp shives particles (length) on compressive strength and other parameters of lightweight composites is studied. Sample of hemp shive with a wide lengths distribution (8 – 0.2mm; mean length: 33.7mm) and two separated fractions (< 4mm and 4-8mm) with mean length of particles 7.3mm and 27.7mm were used in the experiments. Composites based on MgO-cement as a binder with a constant ratio of hemp shives (40 vol. %) were prepared. Density, compressive strength, thermal conductivity and water absorbability of composites after 28 days of hardening were tested. Effect of mean length of hemp shives slices on the above mentioned characteristics of fibrous composites was confirmed. Values of density and compressive strength of fibrous composites increase with decreasing length of hemp shive slices. The lowest value of water absorbability was recorded for composite based on fraction with short length of hemp shives slices. The impact of mean length of hemp shive slices on thermal conductivity parameter was not confirmed
Design of a Customized Neck Orthosis for FDM Manufacturing with a New Sustainable Bio-composite
The interest in developing customized external orthopaedic devices,
thanks to the advent of Additive Manufacturing (AM), has grown in recent
years. Greater attention was focused on upper limb casts, while applications to
other body’s parts, such as the neck, were less investigated. In this paper the
computer aided design (CAD) modelling, assessment and 3D printing with
fused deposition modelling (FDM) of a customized neck orthosis are reported.
The modelling, based on anatomic data of a volunteer subject, was aimed to
obtain a lightweight, ventilated, hygienic and comfortable orthosis compared to
the produced medical devices generally used for neck injuries. CAD models
with different geometrical patterns, introduced for lightening and improving
breathability, were considered, specifically, a honeycomb pattern and an elliptical
holes pattern. These models were structurally assessed by means of finite
elements analysis (FEA). Furthermore, an innovative composite material was
considered for 3D printing. The material, Hemp Bio-Plastic® (HBP), composed
by polylactic acid (PLA) and hemp shives, offers different advantages including
lightweight, improved superficial finish and antibacterial properties. The results
obtained in terms of design methodology and manufacturing by 3D printing of a
prototype have shown the feasibility to develop customized cervical orthoses,
with potentially improved performance with respect to cervical collars available
on the market also thanks to the use of the innovative composite material
Wpływ alternatywnego spoiwa na właściwości kompozytu z włóknami konopnymi
Composites based on natural fibres as organic filler are studied for several years
because traditional building materials such as concrete are increasingly being
replaced by advanced composite materials (fibre reinforced cement). The current
trend in the construction industry is the effort to achieve sustainable development
using rapidly renewable material resources instead of limited raw materials as well
as using alternative materials. The need for development of promising and
environmentally friendly materials is related to the industrial interest in the use of
natural plant fibres as reinforcement into lightweight composites. The attention is
given to hemp fibres as a substitute for synthetic fibers in lightweight composites
due to their unique mechanical, thermal insulation, acoustic and antiseptic
properties. Optimizing the adhesion of hemp plant fibre to the inorganic matrix
in the composite is related to the modification of hemp fibers and/or the
appropriate option and treatment of binder. In this paper, the attention is given
to the study properties of composite based on hemp hurds as filler and alternative
binder (MgO-cement). The hemp as a building composite component is rapidly
renewable, carbon-negative, non-toxic, mildew-resistant and pest-free. Cement
based on MgO seems to be a suitable binding agent for composites based on hemp
hurds. Experimental work is focused on the study of impact of alternative binder
on the selected properties of prepared lightweight composites and variation
of mixtures based on hemp hurds and alternative binder focused on the MgO and
SiO2 component (silica sand and silica fume in variation). The evaluation of the
physical and mechanical properties of hemp hurds composites with alternative
binder is given. The results have shown that by incorporating hemp hurds into
a magnesium oxide cement matrix it is possible to prepare materials with suitable
thermal insulating properties usable in non-load-bearing structures.Od kilku lat badane są kompozyty na bazie włókien naturalnych jako wypełniacze organiczne,
ponieważ tradycyjne materiały budowlane, takie jak beton, są coraz częściej zastępowane
zaawansowanymi materiałami kompozytowymi (cement wzmacniany włóknami). Obecną tendencją
w branży budowlanej jest dążenie do osiągnięcia zrównoważonego rozwoju przy wykorzystaniu
szybko odnawialnych surowców, a nieograniczonych surowców, a także przy użyciu alternatywnych
materiałów. Potrzeba opracowania ekologicznych dla środowiska materiałów jest związana
z przemysłowym wykorzystaniem naturalnych włókien roślinnych jako zbrojenia do lekkich
materiałów kompozytowych oraz włókien konopnych jako substytut włókien syntetycznych
w lekkich kompozytach ze względu na ich unikalne własności mechaniczne, termoizolacyjne,
akustyczne i antyseptyczne. Optymalizacja przyczepności włókna roślinnego konopi do matrycy
nieorganicznej w kompozycie jest związana z modyfikacją włókna konopnego i/lub odpowiednią
opcją i obróbką spoiwa. W niniejszym dokumencie zwrócono uwagę na właściwości badawcze
kompozytu bazującego na opasach konopnych (w odcieniach drewna konopi) jako wypełniacza
i alternatywnego środka wiążącego (MgO-cement). Konopie jako komponent złożony z budynków są
szybko odnawialne, są odporne na węgiel, nietoksyczne, odporne na pleśń i wolne od szkodników.
Wydaje się, że cement na bazie MgO jest odpowiednim środkiem wiążącym dla kompozytów na
bazie konopi. Eksperymentalne prace koncentrują się na badaniu termicznego przetwarzania
naturalnego surowego materiału magnezytowego do jego późniejszego wykorzystania jako
alternatywnego składnika wiążącego do lekkich materiałów kompozytowych oraz zróżnicowania
mieszanek kompozytowych opartych na opaskach konopnych i alternatywnym środku wiążącym
skupionym na składniku MgO i SiO2. Ocenę fizycznych i mechanicznych właściwości konopnych
prasuje kompozyty z alternatywnym spoiwem. Wyniki wykazały, że poprzez włączenie konopnych
włókien do matrycy cementowej tlenku magnezu można przygotować materiały o odpowiednich
właściwościach termoizolacyjnych użytych w konstrukcjach nie obciążających
Properties of composites incorporating cellulosic fibers
Nowadays, with the understanding of the importance of the green building concept, there is a constantly increasing demand for ecological construction materials. The application of raw materials from renewable sources such as wood, plants and waste to building materials preparing has gained a significant interest in this research area. With the consideration of environmental consciousness, natural fibers are biodegradable so as they can alleviate the problem of massive solid waste produced and relief the pressure of landfills, they are used for replacing other non-degradable materials for product development. In this experimental work, wood pulp and recycled waste paper fibers in addition 0.2%, 0.3% and 0.5% were used. The fiber cement composites were subjected to a characterization of their composition including the assessment of a complex set of basic physical and mechanical properties after 7 and 28 days of hardening. Experimental results show that application of small amount of cellulosic fibers lead to a reduction of density up to 6% when compared with the reference composite. However, cement composites based on wood pulp showed better mechanical properties such as compressive and flexural strength in comparison with cement composites with recycled waste paper fibers