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Micro- and Nanostructured Polymer Blends: State of the Art, Challenges, and Future Prospects
Published in Charef Harrats, Sabu Thomas, Gabriel Groeninckx, Micro- and Nanostructured Multiphase Polymer Blend Systems, 2005
Sabu Thomas, Charef Harrats, Gabriel Groeninckx
The incorporation of rigid (amorphous or semicrystalline) polymers into thermoplastics will enhance stiffness particularly at temperatures above the Tg of the thermoplastic polymer. Of course, the inclusion of a rigid polymer phase is one of the well known ways of raising the heat distortion temperature (HDT) of many polymer systems. HDT is the temperature at which the deflection of a specified part exceeds a critical value under load and corresponds to a certain value of modulus. It has been shown that for automotive applications, it is important to increase the HDT to avoid excessive deformations. This can be achieved by the incorporation of rigid (amorphous or semicrystalline) polymers. However, unlike toughening, a good correlation has not been established between the microstructure and the tensile properties of polymer blends (123).
Particulate-Reinforced Polylactic Composites: Synthesis, Properties, and Applications
Published in Sefiu Adekunle Bello, Hybrid Polymeric Nanocomposites from Agricultural Waste, 2023
Collieus Lebudi, Babatunde Abiodun Obadele, Oluseyi Philip Oladijo, Enoch Nifise Ogunmuyiwa
Low dimensional stability – The Tg range of PLA is 50–60°C, which is relatively lower than that of competing petroleum-based polymers. As the Tg range determines the allowable service temperatures of most applications, this limits the use of PLA in high-temperature environments exceeding Tg. Beyond Tg, the physical and mechanical properties of polymers begin to drastically change as they become more rubbery. Lower Tg values are often described by low heat distortion or deflection temperature (HDT).
Nanocomposites for food packaging applications
Published in Badal Jageshwar Prasad Dewangan, Maheshkumar Narsingrao Yenkie, Novel Applications in Polymers and Waste Management, 2018
It was reported by many researchers that significant improvement in the heat deflection temperature (HDT) cannot be achieved by incorporating convention filler. It is possible to improve HDT by adding nanoclays, nanoparticles, or more commonly nano-reinforcement in polymers rather than conventional fillers.30, 37 Improvement in HDT was reported by Kojima in 1993 by 90°C, in case of Nylon 6 and organically modified clay or layered silicate nanocomposites.43
A circular economy use of waste wood sawdust for wood plastic composite production: effect of bio-plasticiser on the toughness
Published in International Journal of Sustainable Engineering, 2020
Nawadon Petchwattana, Phisut Naknaen, Borwon Narupai
HDT is one of the significant parameters indicating the service temperature of polymers as well as polymer composites. Figure 6 shows the HDT value for neat PLA, PLA/WS and plasticised PLA/WS composites. The HDT value of neat PLA was less than 60°C. With the addition of WS, the HDT value of the composite increased to more than 85°C. However, it gradually decreased with the tributyrin content down to less than 60°C when tributyrin was added at 15 wt%. This behaviour was expected and generally observed in other plasticised PLA systems. The HDT of PLA composite significantly reduced with the ELO from around 54.5°C to less than 50°C (Balart et al. 2016). Plasticising PLA with octyl epoxy stearate (OES) reduced the HDT of PLA from 47.6°C to 46.6°C (Ferri et al. 2016a). With maleinised linseed oil (MLO) the HDT of PLA composite was also dropped from 49.9°C down to 44.8°C (Ferri et al. 2016b).
Interlaminar, free vibration, HDT and water absorption properties of braided flax woven fabric PLA biocomposites
Published in The Journal of The Textile Institute, 2023
Sateeshkumar Kanakannavar, Jeyaraj Pitchaimani
Heat-deflection-temperature (HDT) is a temperature required to achieve a deflection of 0.25 mm at 0.455 MPa applied pressure. HDT provides a maximum temperature limit for a material used in thermal applications. HDT behaviour of the pure PLA and braided flax fibre composites is indicated in Figure 14. It presents that the pure PLA has a HDT value of 54.80° C and it is increased with fibre reinforcement. It is also noticed that, as the fibre weight percentage increased the HDT value of the composites also improved proportionately. Increase in fibre content from 11% to 33% HDT value also increases from 88.66 °C to 127.67 °C, which is 61.78% to 132.97% higher than the pure PLA. Natural fibres (flax fibres) are bad conductors of heat (Kymäläinen & Sjöberg, 2008), reinforcement of these fibres improves the PLA polymer thermal-stability (Kanakannavar & Pitchaimani, 2021; Khuntia & Biswas, 2022). Hence, HDT of the braided flax PLA composites is improved. Also, previous research has shown that good matrix-fibre adhesion improves uniform transfer of heat in the composites and therefore leads to enhanced thermal-stability of the composites (Hong et al., 2017). The NFBF33 showed significant enhancement in HDT, due to the increase in the modulus (stiffness) of the composites which reduces the creep rate under given load (Liu et al., 2005; Liu et al., 2007). This enhancement in HDT is attributed to the strong fibre-matrix interfacial strength as observed previously by other researchers (Awal et al., 2015; Singh et al., 2008; Huda et al., 2006). The findings of the NFBF strengthened PLA composites (high HDT values) indicate that these composites can be used in applications which require operating temperature higher than pure PLA.