1,720,997 research outputs found
Biodegradable and Compostable PLA-based formulations to replace plastic disposable commodities
No full textNew renewable and environmentally friendly materials through molecular modification and blending of biorelated polymers
No full textDesign of new biodegradable amphiphilic block copolymers containing PVP or PEG as hydrophilic segments
No full textThermal degradation of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephtalate) (PBAT) as a consequence of melt processing: effects on pure materials and their blends
No full textPoly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are biodegradable aliphatic
polyesters, which being semicrystalline and thermoplastic can be processed by conventional methods.
Their blends give interesting materials for industrial packaging applications, due to their increased
ductility as PBAT content increases. However, like many aliphatic polyesters, the PLA matrix degrades
upon melt processing thus affecting the thermo-mechanical features of the blended material. In this
work, we studied the effect of processing at high temperature on the molecular weight distribution,
morphology, and thermo-mechanical properties of both homopolymers, as well as the PLA/PBAT 75/25
blend. Notably, different processing conditions were adopted in terms of temperature (range 150–200 C)
and other relevant processing parameters (moisture removal and nitrogen atmosphere). Analysis of PLA/
PBAT blends indicated that intermolecular chain reactions took place under strong degradative conditions
of PLA, yielding PLA/PBAT mixed chains (copolymers). Increasing amounts of copolymers resulted
in improved phase dispersion and increased ductility, as SEM and mechanical tests indicated. Conversely,
reduced PLA degradation with less copolymer formation, afforded higher modulus materials, owing to
poorer dispersion of the soft phase (PBAT) into the PLA matrix
Amorphous/crystal and polymer/filler interphases in biocomposites from poly(butylene succinate)
No full textPoly(butylene succinate)-hemp composites (PBS-hemp), with hemp content
in the range 0-40 wt.\%, were prepared in the melt and characterized.
This paper focuses on the detailed analysis of the thermal behaviour of
the PBS-hemp composites, investigated by differential scanning
calorimetry (DSC), to enlighten the polymer/fibre interphase features.
The occurrence of specific intermolecular interactions between PBS and
hemp was assessed from specific heat capacity data. Different degrees of
mobility of the PBS amorphous segments were found at the
amorphous/crystal interphases. A broadening of the bulk glass transition
was observed, and attributed to the presence of polymer segments
slightly constrained. Moreover, a rigid amorphous fraction that
devitrifies at temperatures higher than the bulk glass transition,
partly before the melting region and partly simultaneously with the
fusion, was observed and quantified, and attributed to the presence of
major constraints probably occurring in geometrically restricted areas.
(C) 2012 Elsevier B.V. All rights reserved
Radical functionalization of poly(butylene succinate-co-adipate): Effect of cinnamic co-agents on maleic anhydride grafting
No full textMaleic anhydride (MAH), trans cinnamic acid (AcCin) and ethyl cinnamate
(EtCin) were radically graft onto poly(butylene succinate-co-adipate)
(PBSA). Samples were prepared in Brabender at 175 degrees C by addition
of increasing amounts of MAH, AcCin, EtCin and their combinations, i.e.
MAH/AcCin and MAH/EtCin, setting DCP content in the 0.2-0.6 wt\% range.
Monomer grafting was quantitatively determined by FT-IR. MAH grafting
degrees (FD(M)) resulted up to 1 molt Conversely, AcCin grafting degrees
(FD(A)) were found almost negligible in all cases. EtCin was found
grafted in the 0.3-1.0 mol\% range when the binary system MAH/EtCin was
applied. Same MAH feeds returned almost doubled MAH grafting degrees
(FD(M)) when AcCin was the stoichiometric co-agent, and even three times
higher FD(M) when EtCin was the stoichiometric co-agent. On accounts of
all the collected results, a kinetic model of the investigated systems
is proposed. (C) 2011 Elsevier Ltd. All rights reserved
Development of new PLA-based biodegradable compounds for micro-irrigation applications
No full textNew biodegradable compounds having high renewable resources starting
materials content were developed and formulated at Lab, pilot and
industrial level. Pipes were prepared using the here developed
compounds, and perfectly mimic the mechanical behavior as well as the
chemical resistance of the currently used polyethylene based materials.
This work is currently developed within the EC founded HYDRUS project
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