A Process for the Synthesis and Use of Highly Aromatic Organosilanes as Additives for Poly(Vinyl Chloride) Films

Abstract

Three organosilanes were synthesized in good yields from the condensation of 4,4′,4″-((phenylsilanetriyl)tris(oxy))tribenzaldehyde and 4-substituted anilines under acidic conditions. The structure of the organosilanes was confirmed using a variety of techniques. Organosilanes were mixed with poly(vinyl chloride) (PVC) and homogenous films were produced. The effect of long-term irradiation on the films containing organosilanes was tested using various methods. Monitoring the infrared spectra of PVC films before, during and after irradiation processes showed the formation of side products comprising polyene, carbonyl and hydroxyl groups. The intensities of absorption bands due to these functional groups were much lower in the presence of organosilanes as compared to the blank film. Also, the decrease in the weight and molecular weight of PVC films after irradiation was lower in the presence of organosilanes. Additionally, there was a minimal surface change of irradiated PVC in the presence of organosilanes. Clearly, organosilanes act as inhibitors, particularly the one containing the hydroxyl group, for the photodegradation of PVC. Different mechanisms were proposed to speculate the role played by organosilanes in stabilizing PVC against long-term ultraviolet light exposure.

Modifications of Polymers through the Addition of Ultraviolet Absorbers to Reduce the Aging Effect of Accelerated and Natural Irradiation

“…Recently, we synthesized a range of UV stabilizers (e.g., aromatics, heterocycles, Schiff bases, organometallic complexes, and polyphosphates) and tested their efficiency for the stabilization of polymers [ 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ]. These additives, at a low concentration of 0.5% by weight, led to a significant improvement in the photostability of polymers.…”

Photostabilization of Poly(vinyl chloride) Films Blended with Organotin Complexes of Mefenamic Acid for Outdoor Applications

“…Various additives have been used to overcome the problems associated with the creation of side products and small fragments from PVC when exposed to UV irradiation. Common PVC additives include aromatics [9][10][11][12], polyphosphates [13][14][15], Schiff bases [16][17][18][19][20][21], carbon nanotubes [22], and titanium dioxide [23][24][25][26][27], among many others [28][29][30].…”

Studying the photodecomposition rate constant and morphology properties of modified poly(vinyl chloride) with novel Schiff's bases

“…Here, photostabilizers protect PVC films from photodegradation by converting solar energy to dissipate heat without harming the chemical structure of the polymer. 27 The connection of the Schiff base with the polymeric chain might improve the PVC polymer's performance by reducing the cross-linking for polymeric chains and increasing the links of polymer chains. These additives are capable of immediately absorbing the UV light and gently disperse the energy to maintain the polymeric chains unbroken.…”