scholarly journals Environmentally Friendly Polymer Compositions with Natural Amber Acid

2021 ◽  
Vol 22 (4) ◽  
pp. 1556
Author(s):  
Malgorzata Latos-Brozio ◽  
Anna Masek
Keyword(s):  
Succinic Acid ◽  
Color Change ◽  
Accelerated Aging ◽  
Polymeric Materials ◽  
Spectrophotometric Analysis ◽  
Aliphatic Polyesters ◽  
Resistance To Oxidation ◽  
Time In Service ◽  
Oxidative Effect ◽  
Biodegradable Composition

Few scientific reports have suggested the possibility of using natural phenolic acids as functional substances, such as stabilizers for polymeric materials. The replacement of commercial stabilizers in the polymer industry can be beneficial to human health and the environment. The aim of this study was to obtain biodegradable composition of polylactide (PLA) and polyhydroxyalkanoate (PHA) with natural amber (succinic) acid. The materials were subjected to controlled thermooxidation and solar aging. The research methodology included thermal analysis, examination of surface energy, mechanical properties and spectrophotometric analysis of the color change after aging. The samples of aliphatic polyesters containing from 1 to 2 parts by weight of succinic acid were characterized by increased resistance to oxidation (DSC analysis). Natural acid, preferably at a concentration of 1–1.5 parts by weight, acted as a stabilizer in the polymer compositions. On the other hand, materials that had amber acid above 2 parts by weight added were more susceptible to oxidation (DSC). They also showed the lowest aging coefficients (K). The addition of acid at 2.5–4 parts by weight caused a pro-oxidative effect and accelerated aging. By adding amber acid to PLA and PHA, it is possible to design their time in service and their overall lifetime.

scholarly journals Plant-Origin Stabilizer as an Alternative of Natural Additive to Polymers Used in Packaging Materials

2021 ◽  
Vol 22 (8) ◽  
pp. 4012
Author(s):  
Angelika Plota ◽  
Anna Masek
Keyword(s):  
Color Change ◽  
Polymeric Materials ◽  
Packaging Materials ◽  
Polymer Mixtures ◽  
Oxidation Induction Time ◽  
Research Technology ◽  
Resistance To Oxidation ◽  
Colorimetric Indicator ◽  
Natural Additive

Over the past 25 years, cannabis plants have gained major popularity in the research community. This study aimed to evaluate the antioxidant capacity and stabilization efficiency of cannabidiol (CBD) extract in two different polymers: polylactide (PLA) and ethylene–norbornene copolymer (Topas) that are used in packaging materials more often. The research technology included weathering in a special chamber, surface free energy and color change measurements, surface morphology and Fourier-transform infrared spectroscopy (FTIR) analysis, thermogravimetry, and determination of the oxidation induction time or temperature (OIT) values, based on which the effectiveness of the cannabidiol extract could be estimated. Obtained results showed that the addition of CBD to polymer mixtures significantly increased their resistance to oxidation, and it can be used as a natural stabilizer for polymeric products. Moreover, samples with cannabidiol changed their coloration as a result of weathering. Therefore, this natural additive can also be considered as a colorimetric indicator of aging that informs about the changes in polymeric materials during their lifetime. On the other hand, surface properties of samples with cannabidiol content did not alter much compared to pure Topas and PLA.

Assessment of Color Stability of Treated Leathers with Silicone Oil and Polyethylene Glycol

2014 ◽  
Vol 1 (1) ◽  
pp. 24-34
Author(s):  
Alireza K. ◽  
Hossein Ahmadi ◽  
Mohsen Mohammadi
Keyword(s):  
Ascorbic Acid ◽  
Polyethylene Glycol ◽  
Treatment Process ◽  
Color Change ◽  
Silicone Oil ◽  
Accelerated Aging ◽  
Color Stability ◽  
Antioxidant Additive ◽  
Before And After ◽  
Aesthetic Values

Lubricants and leather dressings are the most common treatments of dry and water logged historical leathers. Color change has a great importance during the time and treatment process, due to visual and aesthetic values of historic leather relics. Polyethylene glycol (PEG) and silicone oil (SiO) are frequently used leather dressings in the conservation procedures. Therefore, color stability of treated leathers with PEG and SiO were investigated before and after heat accelerated aging. Moreover, application of ascorbic acid was evaluated as an antioxidant additive for PEG (PEG+AA).Color change after treatment and aging were studied by colorimetry technique in the CIE *L*a*b system. Results indicated to severe color alteration in PEG treated and aged leathers with or without ascorbic acid. Whereas, SiO treated samples showed better stability and minimum color shift after aging. Silicone oil was characterized as the best dressing for historical leathers with compared to PEG and PEG+AA, due to its high stability and aesthetical properties.

Evaluation of Color Changes of Different Resin Cements in Feldspathic Ceramic Crowns After Accelerated Aging: An In Vitro Research

2021 ◽  
pp. 232020682110443
Author(s):  
Murat Eskitaşçıoğlu ◽  
Mehmet Şerif Akdeniz ◽  
Beyza Ünalan Değirmenci
Keyword(s):  
Color Change ◽  
Accelerated Aging ◽  
B Value ◽  
Resin Cements ◽  
Color Changes ◽  
A Value ◽  
L Value ◽  
Ceramic Crowns ◽  
The Times

Aims: To evaluate the color changes that occur after accelerated aging in feldspathic ceramic crowns cemented with three different dual-cured resin cements. Materials and Methods: For each of the A2-colored RelyX U200, G-CEM LinkForce, and Panavia V5 cement groups, 45 dies from A2-colored zirconia blocks and 45 crowns from CEREC blocks were prepared. Color measurements after 24 h of cementation (T1) and after cycles of aging of 1750 (T2), 3500 (T3), and 7000 (T4) in the thermal cycle device were made using SpectroShade Micro device. The coordinates of the color were used L*, a*, and b* as base and the color change was calculated with ∆ E00 in determining the color. One-way analysis of variance test was used to compare the times in terms of ∆ L*, ∆ a*, and ∆ b* values. Results: It was found that ∆ L* value decreased significantly in period of the T2, T3, and T4 times compared to T1 in all groups ( P < .05), whereas the change between period of T2, T3, and T4 times was not significant ( P > .05). The ∆ a* value increased significantly in the period of T3 and T4 times compared to T1 in the only G-CEM LinkForce group, whereas the ∆ b* value increased significantly in the period of T4 time compared to T1 in the only Panavia V5 group. The changes in ∆ E00 values, which were observed in all period of times, were found to be between 0.43 and 1.04, 0.43 and 1.43, and 0.40 and 0.97 in RelyX U200, G-CEM LinkForce, and Panavia V5 groups, respectively. Conclusion: After accelerated aging, it was found that the color of all cements became darker and the G-CEM LinkForce group turned red and the Panavia V5 group turned yellow. However, it was found that the color changes that occurred were within clinically acceptable visible levels.

Degradation Behaviors of Biodegradable Aliphatic Polyesters and Polycarbonates

2020 ◽  
Vol 14 (2) ◽  
pp. 155-168 ◽  
Author(s):  
Yonghang Xu ◽  
Fangya Zhou ◽  
Danmin Zhou ◽  
Jintang Mo ◽  
Huawen Hu ◽  
...  
Keyword(s):  
Biodegradable Polymers ◽  
Degradation Mechanism ◽  
Polymeric Materials ◽  
Degradation Process ◽  
Biodegradable Plastics ◽  
Research Progress ◽  
Aliphatic Polyesters ◽  
Depth Study ◽  
Degradation Behaviors ◽  
And Control

Aliphatic polyesters and polycarbonates such as polylactide (PLA), polycaprolactone (PCL) and poly(propylene carbonate) (PPC), are well known as biodegradable, biocompatible and environmental-friendly polymeric materials, which have been widely used in various areas ranging from packaging to biomedical materials. The production and usage of biodegradable plastics can greatly alleviate the safety and environmental concerns because of the fairly short degradation periods and low toxicity of catabolite. During the degradation process of polymers, obvious changes appear in polymer structures and the physiochemical properties. Therefore, it is necessary to regulate and control the degradation behaviors and periods of biodegradable plastics such as polyesters and polycarbonates, which is significant for their more widespread popularization and applications. In this context, it is highly desirable to make a review contribution in this field so as to better understand the recent research progress on polymer degradation behaviors and kinetics, as well as the future prospect of biodegradable polymers. Herein, this paper reviews the research progress on the degradation behaviors of biodegradable polyesters and polycarbonates materials including PLA, PCL and PPC. Through an in-depth study of various internal/external factors, the degradation mechanism of these polymers is unraveled, which will motivate future studies into the synthesis of novel biodegradable polymers and the understanding of their degradation behavior on the molecular level.

scholarly journals Effect of Staining Solutions on the Color Stability of Conventional and Bulk Fill Nanohybrid Resin Composites: A Spectrophotometric Analysis

2017 ◽  
Vol 2 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Jayaprakash Thumu ◽  
Anirudh Kadiyala ◽  
Indira Priyadarshini Bollu ◽  
Srinidhi Vishnu Ballullaya ◽  
Srihari Devalla
Keyword(s):  
Color Change ◽  
Color Stability ◽  
Spectrophotometric Analysis ◽  
Resin Composites ◽  
Water Control ◽  
Group Iii ◽  
Color Changes ◽  
Group I ◽  
Immersion Period ◽  
Friedman's Test

ABSTRACT Aim This study is aimed to evaluate the effect of staining solutions on the color stability of bulk fill and conventional nanohybrid resin composites (RCs) when subjected to various immersion periods. Materials and methods A total of 120 cylindrical Teflon molds (4 × 4 mm) were obtained and divided into four groups of 30 each. Molds of groups I and II were filled with Tetric N Ceram Bulk Fill (Ivoclar Vivadent, Schaan, Liechtenstein) and Filtek Bulk Fill (3M ESPE, St. Paul, MN, USA). Molds of groups III and IV were filled with Tetric N Ceram (Ivoclar Vivadent) and Filtek Z250 XTE (3M ESPE) incremental fill RC. Photo-activation was performed and specimens were incubated. Spectrophotometer analysis was done according to Commission Internationale d'Eclairage Lab color scale. After taking the baseline measurements, 10 samples from each group were immersed in distilled water (control, subgroup a), tea (subgroup b), and coffee (subgroup c) respectively, for 1, 7, and 30 days. The color values of each specimen were remeasured and color change value (E*ab) was calculated after 1, 7, and 30 days. Data were analyzed by Friedman's test and Mann–Whitney U-test; p < 0.05 is considered to be statistically significant. Results Group III specimens showed perceptible color changes at 30-day immersion period in coffee and tea. In group I specimens, color changes were perceptible at 7- and 30-day immersion periods in coffee and only 30-day immersion period in tea. Groups II and IV specimens showed perceptible color changes after all immersion periods in coffee and after 30 days in tea. Conclusion It can be concluded that Tetric N Ceram has less color change than the other nanohybrid RCs investigated when immersed in coffee and tea after various immersion periods. How to cite this article Thumu J, Kadiyala A, Bollu IP, Ballullaya SV, Devalla S. Effect of Staining Solutions on the Color Stability of Conventional and Bulk Fill Nanohybrid Resin Composites: A Spectrophotometric Analysis. J Oper Dent Endod 2017;2(1):1-5.

scholarly journals The Application of (+)-Catechin and Polydatin as Functional Additives for Biodegradable Polyesters

2020 ◽  
Vol 21 (2) ◽  
pp. 414 ◽  
Author(s):  
Malgorzata Latos-Brozio ◽  
Anna Masek
Keyword(s):  
Wide Spectrum ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
X Ray Diffraction ◽  
Aliphatic Polyesters ◽  
Biodegradable Polyesters ◽  
Functional Additives ◽  
Multifunctional Additives ◽  
Free Energy Analysis ◽  
New Generation

Plant polyphenols are a huge group of compounds with a wide spectrum of applications. Substances from this group have been used in polymer materials such as stabilizers, dyes, indicators, fungicides, and bactericides, especially in new generation packaging materials. The aim of this study is to obtain environmentally friendly materials based on the biodegradable aliphatic polyesters, polylactide (PLA) and polyhydroxyalkanoate (PHA), with plant functional additives, (+)-catechin and polydatin. These natural polyphenols (polydatin and (+)-catechin) have not been used so far in polymer materials (especially in biodegradable polyesters) as stabilizers, dyes, and indicators of aging. The application of polydatin and (+)-catechin as multifunctional additives for biodegradable polymers is a scientific novelty. This paper presents the following analyses of polyester materials: SEM microscopy, wide angle x-ray diffraction, mechanical properties, thermal analysis, surface free energy analysis, and determination of change of color after controlled UV exposure, thermal oxidation and weathering. Both PLA and PHA polyesters were characterized by higher resistance to oxidation and greater resistance to degradation under the influence of UV radiation. In addition, (+)-catechin was used simultaneously as a dye and an indicator of the aging time of polymeric materials. In contrast, polydatin did not dye polymers, but was a very good indicator of their lifetime, changing color under the influence of various external factors. Both polyphenols can be successfully used as natural additives for pro-ecological polyesters.

Using polaroid zinc oxide nanocomposites in strengthening a historical printed paper: application to “Annales Agricoles” – 1829 AD

2020 ◽  
Vol 49 (5) ◽  
pp. 369-375
Author(s):  
Rushdya Rabee Ali Hassan
Keyword(s):  
Zinc Oxide ◽  
Color Change ◽  
Accelerated Aging ◽  
Fiber Surface ◽  
Strengthening Effect ◽  
Zno Nps ◽  
Content Type ◽  
Nano Zinc Oxide ◽  
Reflectance Analysis ◽  
Nano Zinc

Purpose What is the behavior of nano-polaroid in strengthening weak paper? What is the effect of adding nano-zinc oxide to nano-polaroid? This paper aims to answer these questions. Design/methodology/approach A number of weak historical papers dating back to 1829 AD were treated with 2% of nano-polaroid and polaroid zinc oxide nanocomposites, respectively. After dryness, the samples were subjected to ultraviolet–ozone accelerated aging. Then, the effectiveness of the treatment was defined using the mechanical properties measurement, pH measurement, the chromatic change, scanning electron microscope investigation of the fibers surface and attenuated total reflectance analysis. Findings Results revealed that N-polaroid strengthened the fiber surface without reducing the gloss of ink. With the loading of nano-zinc particles onto N-polaroid, the strengthening effect increased, especially after the aging processes where the tensile and elongation values reached the highest value. Not only this but also the nano-polaroid coated with ZnO NPs reduced the color change and yellowness during aging, where the ΔE value reached to 3.3 (an acceptable degree of change, not monitored by the naked eye). The acidity of the treated paper also decreased significantly after the treatment and the aging. The microscopic images detected the improvement of the fibers’ structure where the fibers were swollen by the absorption of nanocomposites, which can be attributed to ZnO (NPs) that decreased the contact angle between the cellulose and the N-polaroid, which helped in filling the primary cells of fibers. Originality/value The study addressed the reinforcement of the printed paper samples using nano-polaroid and ZnO polaroid nanocomposites.

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