Novel silicon microparticles to improve sunlight stability of raw polypropylene

Abstract

a b s t r a c tOxidation of polyolefins by ultraviolet/visible irradiation is a significant limitation for their use in several technological applications. The use of high-tech additives such as silicon microparticles becomes a compositing strategy that can improve the performance of these materials at long-term service conditions. Silicon particles were added to non-additivated raw polypropylene (PP) prepared by hot melt extrusion and subjected to accelerated sunlight irradiation tests. The stability of thermal properties, mechanical performance and thermal decomposition behaviour of composites was evaluated by differential scanning calorimetry, dynamic mechanical-thermal analysis and thermogravimetry. This paper shows the potential of silicon microparticles to protect PP from degradation during both processing and accelerated sunlight irradiation. The addition of polydisperse silicon microparticles to the raw polypropylene preserved the appearance and improved the thermal behaviour, mechanical properties and thermal stability. It was found that silicon particles at 5 wt% provided a suitable protection of raw non-additivated PP against sunlight irradiation.

Long-term properties and end-of-life of polymers from renewable resources

“…Photodegradation can conduce to Norrish reactions and/or crosslinking reactions, or oxidative processes [233]. Polymers such as PLA or PCL [234] properties, such as tensile or impact resistances or show the performance of additives to protect them such as ZnO [240], Si colloids [241] and other stabilizers to prevent them from degradation [242]. These techniques allow setting not only UV wavelengths, but also temperatures, day-night cycles, or controlled floating, rain or humidity.…”

Mechanical recycling of polylactide, upgrading trends and combination of valorization techniques

“…The use of plasticizers to improve the processability and versatility of performance of PLA is of relevant importance and therefore the mechanism of degradation of these blends during mechanical recycling were investigated by Brüster et al [66]. or UV-protection [83] can be improved through proper additives but this may incur an extra payment to be studied in each case to achieve the optimal ratio between properties and cost. For example, the intermolecular transesterification occurring during the melt [84], [85] of PLA could be minimized by stabilizers such as 1-4 dianthraquinone [80] or benzoyl peroxide [86].…”

Protection of high‐density polyethylene–silicon composites from ultraviolet–visible photodegradation

“…A Suntest XLS + (Chicago, IL), which used a xenon lamp with a solar standard filter, which cut the λ below 290 nm to simulate the UV–vis spectrum, was used. The UV–vis photoirradiation time in the exposure system was converted to the approximated real sun exposure time reference in Jacksonville, Florida with an annual total radiant energy of 5800 MJ/m 2 (λ = 280–3000 nm); this corresponded to 3248 MJ/m 2 in the λ range 280–800 nm . The hours of photoirradiation, the total radiant energy for that time, and the corresponding outdoor exposure times are given in Table .…”

“…In particular, sensitive parameters such as T c , T m , and the mass loss of the main decomposition peak temperature ( T d ) can be used to correlate the potential preventive effects toward sunlight degradation with the amount of Si present in high‐density polyethylene (HDPE)–Si composites. A first attempt reported by Gil‐Castell et al . showed preliminary promising results about the effects of Si microparticles on the durability of raw polypropylene against UV–vis degradation.…”