Sunscreen Performance of Lignin from Different Technical Resources and Their General Synergistic Effect with Synthetic Sunscreens

Abstract

Five types of industrial lignin are blended with a pure cream and a commercial sunscreen lotion. Lignin is found to significantly boost their sunscreen performance. Photostability of the lignin-modified lotions is analyzed. The results show that hydrophobic lignin has better sunscreen performance than hydrophilic counterpart. Sun protection factor (SPF) of the pure cream containing 10% organosolv lignin (OL) reaches 8.66. Small amount of hydrophobic lignin dramatically increases SPF value of the sunscreen lotions. Adding 1% lignin almost doubles the sun lotion’s SPF. Addition of 10% OL to the lotion boosts its SPF from 15 to 91.61. However, it is also found that hydrophilic lignin tends to demulsify the lotions due to an electrostatic disequilibrium. After 2 h of UV radiation, UV absorbance of all the five lignin-modified sunscreen lotions increases up to the limit of measuring instrument. All the lignin types studied in this work are found to have a general synergistic effect with sunscreen actives in the commercial lotion. An effort is also made to elucidate radical mechanisms of the synergy.

Lignin for Nano‐ and Microscaled Carrier Systems: Applications, Trends, and Challenges

“…Stable CLP dispersions have been reported at concentrations up to 3 % ( w / w ) using ethanol as co‐solvent with THF . CLPs exhibit lignin‐typical antioxidant and UV‐protective properties that are useful for instance in sunscreens . Aerosol technology is another approach to prepare lignin nano‐ and microparticles (Figure d) .…”

“…Many recent studies used lignin‐based micro‐ and nanocapsules for sunscreen applications, relying on the natural UV absorbance of lignin and making use of synergistic effects between conventional, normally very hydrophobic sunscreen active substances and lignin . Qiu et al.…”

Rapid pretreatment of Miscanthus using the low-cost ionic liquid triethylammonium hydrogen sulfate at elevated temperatures

“…28,29 The hydrate impurities and sulfur, 32 low polydispersity, 37 and high phenolic hydroxyl group content are important for thermal stabilisation, antioxidant properties 33 and the replacement of phenol. 36 Most lignin available today is derived from paper pulping processes, which are optimised for cellulose characteristics and not necessarily for downstream applications of lignin.…”

Lignin for polymer and nanoparticle production: Current status and challenges

“…The mechanical and thermal performance of the LNPs/PVA films was improved owing to adequate interfacial adhesion between phenolic hydroxyl groups on the shell of LNPs with PVA matrix through hydrogen bonding . Although lignins from different technical sources have different sunscreen performance, the highest sun protection factor (SPF) of pure cream containing hydrophobic lignin (eg, OL) does not meet the basic requirement of daily sunscreen (SPF≥15), while the excess addition of hydrophilic lignin (eg, lignosulphonate) will demulsify the sunscreens . Qian et al prepared lignin‐based sunscreens by blending LNP with pure skin cream.…”

“…[58] Although lignins from different technical sources have different sunscreen performance, the highest sun protection factor (SPF) of pure cream containing hydrophobic lignin (eg, OL) does not meet the basic requirement of daily sunscreen (SPF≥15), while the excess addition of hydrophilic lignin (eg, lignosulphonate) will demulsify the sunscreens. [94] Qian et al [45] prepared lignin-based sunscreens by blending LNP with pure skin cream. The SPF value of the sunscreens reached 15.03 when blending 10% LNP produced from OL, and the SPF decreased with the increased size of LNPs.…”