Green Flame-Retardant Composites Based on PP/TiO2/Lignin Obtained by Melt-Mixing Extrusion

Abstract

Nowadays, highly flammable and harmful plastic materials are used in many daily applications. To prevent burning of materials, other harmful molecules or materials that are not environmentally friendly are added to plastics. To overcome this environmental issue, new materials have been investigated. Lignin, an industrial by-product, is an abundant biopolymer that can be used in fire safety plastics; it is considered a renewable and readily available resource. In this work, PP–TiO2/lignin composites were obtained with TiO2/lignin mixtures through the melt extrusion process, with different weight percentages of nanoparticles (10, 20, 25, and 30 wt.%). The PP–TiO2/lignin composites were characterized by XRD, FTIR, TGA, and SEM. Furthermore, cone calorimetry tests and the mechanical properties were evaluated. Cone calorimetry tests revealed that the introduction of 25 wt.% TiO2–lignin to the PP matrix reduced the peak of heat release rate (PHRR) and total heat release (THR) by 34.37% and 35.45%, respectively. The flame retardancy index (FRI) values of the composites were greater than 1.0 and were classified as good; the highest value of 1.93 was obtained in the PP-30 sample. The tensile tests demonstrated that the flexural modulus of the composites increased gradually with increasing lignin and TiO2 content, and the flexural strength decreased slightly. The use of lignin in PP composites can be an excellent alternative to synthesize new materials with improved flame-retardant properties and which is friendly to the environment.

Activated Carbon-Loaded Titanium Dioxide Nanoparticles and Their Photocatalytic and Antibacterial Investigations

“…The 1365 cm −1 peak represents the secondary amide compounds derived from phenolic plant compounds. The peak at 1218 cm −1 denotes the stretching vibrations of the C-O bond [43][44][45]. The peaks at 898 cm −1 and 516 cm −1 characterised the C-O-Ti-O bonding [46], which recognised the formation of activated carbon-loaded titanium dioxide nanoparticles.…”

Green Flame-Retardant Blend Used to Improve the Antiflame Properties of Polypropylene

“…In Figure 2, the FTIR spectra of polypropylene and polymeric composites with zeolite and lignin are shown. The polypropylene spectrum showed signals at 2917 and 2840 cm −1 characteristics of the CH 2 -bond asymmetrical and symmetrical stretching [27]. At 1454 and 1369 cm −1 , two intense signals assigned to the asymmetric bending of CH 2 were located [28]; finally, in the PP spectrum, smaller signals were observed in the region from 1000 to 800 cm −1 , which are attributed to CH 3 oscillating vibration [29].…”

Hydrophilic cloth by surface modification of polypropylene fabrics with mineral particles

“…[5] In NWF spectrum, all reflections correspond to α form of polypropylene, identifying the main reflections such as (110), (040), ( 130 F I G U R E 4 XRD spectra of mineral particles, NWF, and m-NWF obtained with methodologies A and B and 28.5 , respectively. [21][22][23] The particle coverage degree in modified fabrics can be analyzed as a function of relative peak intensity of zeolite and polypropylene in m-NWF A and m-NWF B spectra. In m-NWF A spectrum, reflections only correspond to zeolite, evidencing that particle coverage is thick.…”