Effect of CaCO3 Nanoparticles on the Mechanical and Photo-Degradation Properties of LDPE

Abstract

CaCO3 nanoparticles of around 60 nm were obtained by a co-precipitation method and used as filler to prepare low-density polyethylene (LDPE) composites by melt blending. The nanoparticles were also organically modified with oleic acid (O-CaCO3) in order to improve their interaction with the LDPE matrix. By adding 3 and 5 wt% of nanofillers, the mechanical properties under tensile conditions of the polymer matrix improved around 29%. The pure LDPE sample and the nanocomposites with 5 wt% CaCO3 were photoaged by ultraviolet (UV) irradiation during 35 days and the carbonyl index (CI), degree of crystallinity (χc), and Young’s modulus were measured at different times. After photoaging, the LDPE/CaCO3 nanocomposites increased the percent crystallinity (χc), the CI, and Young’s modulus as compared to the pure polymer. Moreover, the viscosity of the photoaged nanocomposite was lower than that of photoaged pure LDPE, while scanning electron microscopy (SEM) analysis showed that after photoaging the nanocomposites presented cavities around the nanoparticles. These difference showed that the presence of CaCO3 nanoparticles accelerate the photo-degradation of the polymer matrix. Our results show that the addition of CaCO3 nanoparticles into an LDPE polymer matrix allows future developments of more sustainable polyethylene materials that could be applied as films in agriculture. These LDPE-CaCO3 nanocomposites open the opportunity to improve the low degradation of the LDPE without sacrificing the polymer’s behavior, allowing future development of novel eco-friendly polymers.

Nano‐CaCO3‐embodied polyacrylicacid/dextran nanocomposites for packaging applications

“…This lower change of 2 θ values at higher wt % of CC are due to agglomeration. Similar observations are also obtained from earlier studies, where CC is agglomerated at its higher concentration with low‐density polyethylene . It is noticed that the crystallite size of nano‐CC is changed (mostly increased) during dispersion in D‐ g ‐PAA polymeric matrix.…”

Sustainable biocarbon as an alternative of traditional fillers for poly(butylene terephthalate)‐based composites: Thermo‐oxidative aging and durability

“…The tensile and flexural modulus of the PBT and its composites increased after thermo‐oxidative aging. The increase in modulus could be due to chain degradation (chain scissoring reactions) and recrystallization process which lead to an embrittlement effect of the samples after aging . Realignment, crosslinking of the lower molecular structure chains and the adhesion mechanism between the matrix and filler might be reformed during thermo‐oxidative aging process.…”

The Effect of Calcium Carbonate on the Photo‐Oxidative Behavior of Poly(butylene adipate‐co‐terephthalate)

“…This means that the presence of nanofillers slightly accelerates the degradation of the EF matrix, as already observed in previous works. [ 33–37 ] After 72 h, the films are so brittle that cannot be further handled. Similar comments can be made for tensile strength.…”

“…The effect of nanosized calcium carbonate on the photo‐oxidation behavior of the polymer matrix has been already reported in the literature. [ 33–37 ] In most cases, [ 33,36,37 ] the photoresistance of the polymer matrix was reduced by the presence of the calcium carbonate due to several factors like nucleation effect, impurities, light sensitizers, catalytic action on the oxidation, etc. Other researches, on the contrary, [ 34,35 ] put in evidence the photostabilizing action of the calcium carbonate, underlining how the influence of the filler on the processing of the material plays an important role in the next photo‐oxidation process.…”