Natural volatile antibacterial and anti-mycotoxin tea tree oil (TTO) with rice bran (RB) were used as a solid carrier for achieving a sustained release profile with high antimicrobial efficiency in polyethylene films. Acrylic acid (AAc) monomer was grafted onto a low-density polyethylene (LDPE) through melt blending using a Brabender Plasti-Corder. The low-density polyethylene-grafted acrylic acid (LDPE- g-AAc) was thoroughly characterized by attenuated total reflectance–Fourier transform infrared spectroscopy. LDPE and LDPE- g-AAc (80/20) were mixed with different contents of untreated RB and treated TTO/RB using melt blending to obtain sustainable composites, namely LDPE/LDPE- g-AAc/RB and LDPE/LDPE- g-AAc/TTO-RB, respectively. The effect of the addition of untreated and treated RB on the properties of biocomposites was assessed by using mechanical, barrier, and thermal properties. A prominent decrease in water vapor transmission rate occurred when adding 30 wt% of TTO/RB to LDPE/LDPE- g-AAc blend compared to virgin polymer. This decrease was due to the barrier effect of lignocellulosic material, particularly at high bio-filler content. The prepared biocomposites revealed good thermal stability when compared to virgin LDPE. Moreover, the biodegradability and antimicrobial properties of LDPE/LDPE- g-AAc/TTO-RB biofilms were enhanced with increasing TTO/RB contents from 10 phr to 30 phr due to the combination between LDPE- g-AAc and TTO. The obtained data revealed excellent possibility for using biopolymer grafted with antimicrobial TTO by adding RB for food packaging and biomedical purposes.

Natural fibre-polymer adhesion can be improved by treating the fibre surface or polymer.

ABSTRACT:The synthesis of N-(4-aminodiphenylmethane) acrylamide (ADPMA) was performed through the reaction of 4,4Ј-diaminodiphenyl methane and acryloyl chloride in the presence of triethyl amine. The grafting of AD-PMA onto natural rubber was executed with UV radiation. Benzoyl peroxide was used to initiate the free-radical grafting copolymerization. Natural rubber-graft-N-(4-aminodiphenyl methane) acrylamide (NR-g-ADPMA) was characterized with an IR technique. We studied the effect of aging on the mechanical properties and the swelling and extraction phenomena for acrylonitrile-butadiene copolymer (NBR) vulcanizates, which contained the prepared NR-g-ADPMA and a commercial antioxidant, N-isopropyl-NЈ-phenyl-pphenylenediamine. The prepared antioxidant enhanced both the mechanical properties of the NBR vulcanizates and the permanence of the ingredients in these vulcanizates.

The essential target of this investigation is to valorize an Eichhornia crassipes fiber (ECF) and maleates of Eichhornia crassipes fiber (MoECF) as reinforcing fillers in styrene-butadiene rubber (SBR) composites in terms of the mechanical, acoustical, thermal, and morphological properties. Fourier transforms infrared spectroscopy characterizes the esterification of ECF with maleic anhydride (MA) and the graft of MoECF onto SBR. SBR composites manufactured with different loadings of ECF and MoECF (1, 2.5, 5, 10, and 20 phr). Scanning electron microscope illustrates the MoECF upgrade interfacial adhesion with the SBR matrix. It is observed that 5 and 20 phr of MoECF enhance the tensile strength and elongation at break of SBR composites by 8% and 310%, respectively. 10 phr of MoECF maintains the tensile strength of SBR composite during the accelerated thermal aging course. While 20 phr of MoECF improves the tensile strength of SBR composite by 19% with increment-accelerated thermal aging time to 7 days. The higher loading (10 and 20 phr) of MoECF ameliorates the thermal stability of SBR composites. SBR composite containing 10 phr of MoECF has sound absorption amplitude equal to 0.9 at the frequency of 400 Hz. The sound absorption performance improved within low-frequency regions below 500 Hz with increasing thickness to 2.3 mm.

Styrene butyl acrylate (SBA) copolymer latex nanoparticles which contain vinyltrimethoxysilane as binding agent were prepared using microemulsion polymerization and were used for coating sisal fiber. The structure of SBA and coated sisal fiber (CF) was confirmed by Fourier transform infrared spectroscopy. The effect of the surface coating of sisal fiber (SF) on the SF/natural rubber (NR) composite properties was systematically evaluated through curing characteristics, morphological properties, mechanical properties, water absorption resistance, biodegradability and dynamic mechanical analysis. As indicated from the morphological study, the coating of SF with SBA enhanced the interfacial adhesion between SF and the NR matrix. In addition, the tensile strength was improved by 26.9% and 43% after the addition of 5 and 10 phr (parts per hundred rubber), respectively, of CF to NR. The coating process improved the water resistance of SF/NR composite significantly especially at high SF loading level, where the composite that contained 30 phr CF absorbed 6.7% water compared to 13.2% for the composite containing uncoated sisal fiber (UF). Dynamic mechanical analysis confirmed that the coating process improved the interfacial adhesion between the SF and NR matrix as indicated from the higher values of storage modulus and lower values of maximum loss factor (tan δmax) recorded for composites containing CF compared to those containing UF. © 2021 Society of Industrial Chemistry.

The grafting copolymerization of natural rubber and o-aminophenol was carried out by using tworoll mill machine. The prepared grafted antioxidant, NRgraft-o-AP, analyzed by using Infrared and 1 H-NMR Spectroscopy techniques. The thermal stability, mechanical properties, and ultrasonic attenuation coefficient were evaluated for NBR vulcanizates containing the commercial antioxidant, PBN, and the prepared grafted antioxidant, NR-graft-o-AP, and the control vulcanizate. Results of the thermal stability indicate that the prepared NR-graft-o-AP can protect NBR vulcanizate against thermal treatment much better than the commercial antioxidant, PBN, and control mix, respectively. The prepared grafted antioxidant improves the mechanical properties of NBR vulcanizate.

T HE TARGET of this work is to choose a suitable nanoparticle for preparing a highly ultraviolet (UV)-shielding from poly (methylmethacrylate) (PMMA) nanocomposites at low concentration and to decrease the destructive effects of UV radiation. Morphologies of the synthesized nanoparticles were investigated by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). Whereas, pure PMMA and its nanocomposites were characterized by using dynamic mechanical analysis (DMA), tensile testing, UV-visible spectra (T%), and thermogravimetric analysis (TGA). The obtained results showed a good correlation between the tensile properties, DMA and TGA analysis depending on the type of nanoparticles used in the PMMA matrix, especially in case of ZrO 2 and ZnO. Furthermore, UV-vis spectra were analyzed ranging from 200 nm to 800 nm. It showed that UV radiation is significantly blocked from 100% to 0.2 % in the UV range between 200 nm and 360 nm for pure PMMA and to 0.08 % for PMMA/CeO 2 nanocomposite and to 0.01 % for PMMA/ CeO 2 with various types of nanoparticles. After 360 nm, pure PMMA and PMMA/CeO 2 were a little bit affected by UV lights, whereas the PMMA based on different nanoparticles was not affected. This result demonstrates that these nanocomposites could be strongly candidates for the sunscreens or for several fields that related to the UV photodegradation effects.

Monomeric antioxidants are widely used as effective antioxidants to protect polymers against thermal oxidation. Low molecular weight antioxidants are easily lost from polymer through migration, evaporation, and extraction. Physical loss of antioxidants is considered to be major concern in the environmental issues and safety regulation as well as long life time of polymers. The grafting copolymerization of natural rubber ando-aminophenol was carried out by using two-roll mill machine. The prepared natural rubber-graft-o-Aminophenol, NR-graft-o-AP, was analysed by using Infrared and1-NMR Spectroscopy techniques. The thermal stability, mechanical properties, and ultrasonic attenuation coefficient were evaluated for NBR vulcanizates containing the commercial antioxidant, N-phenyl--naphthylamine (PBN), the prepared grafted antioxidant, NR-graft-o-AP, and the control vulcanizate. Results of the thermal stability showed that the prepared NR-graft-o-AP can protect NBR vulcanizate against thermal treatment much better than the commercial antioxidant, PBN, and control mix, respectively. The prepared grafted antioxidant improves the mechanical properties of NBR vulcanizate.