scholarly journals Application of Earth Pigments in Cycloolefin Copolymer: Protection against Combustion and Accelerated Aging in the Full Sunlight Spectrum

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3381
Author(s):  
Bolesław Szadkowski ◽  
Małgorzata Kuśmierek ◽  
Przemysław Rybiński ◽  
Witold Żukowski ◽  
Anna Marzec
Keyword(s):  
Mechanical Properties ◽  
Surface Defects ◽  
Accelerated Aging ◽  
Carbonyl Index ◽  
Full Sunlight ◽  
Color Changes ◽  
Aging Resistance ◽  
Mixing Method ◽  
Enhanced Photostability ◽  
Aging Factor

In this paper, we assess various natural earth pigments as potential colorants and stabilizers for ethylene–norbornene copolymer composites. Several cycloolefin copolymer (COC) composites colored with 2 wt% of a selected pigment were prepared using a two-step mixing method. The aging resistance of the polymer composites was investigated in terms of changes to their mechanical properties, following accelerated aging in the full sunlight spectrum (100, 200, 300, 400, and 500 h). Fourier-transform infrared spectroscopy (FTIR), surface energy measurements, and spectrophotometry were used to assess the color changes, surface defects, and morphology of the composites. Thermogravimetric analysis (TGA) was used to study their thermal stability. The combustion characteristics of the prepared COC composites were evaluated based on the microcombustion calorimetry test (MCC). The application of earth pigments resulted in interesting color changes and a significant improvement in the aging resistance of the COC-filled samples, as evidenced by higher aging factor values and lower carbonyl index parameters compared to the reference (COC). The best results were observed for hematite (HM), gold ochre (GO), and red ochre (RO). In addition, the application of earth pigments, especially iron ochre (IO) and red ochre (RO), in COC contributed to a significant reduction in the heat release rate (HRR) values, indicating improved flame retardancy. This research opens the possibility of producing colorful COC composites with enhanced photostability and reduced flammability for use in polymer applications.

scholarly journals Combined Polyhexamethylene Quanidine and Nanocellulose for the Conservation and Enhancement of Ancient Paper

2021 ◽  
Author(s):  
Xiaochun Ma ◽  
Shenglong Tian ◽  
Xiaohong Li ◽  
Huiming Fan ◽  
Shiyu Fu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strain ◽  
Accelerated Aging ◽  
Treatment Method ◽  
Optimum Ratio ◽  
Biocidal Activity ◽  
Polyhexamethylene Guanidine ◽  
Aging Resistance ◽  
Folding Endurance ◽  
Promising Treatment

Abstract Here a new reinforcement and mold-resistant method for ancient books is proposed based on the suspension of nanocellulose (CNCS) and polyhexamethylene guanidine (PHMG). The paper documents were treated with the reinforcement suspension under the optimum ratio obtained by response surface methodology (RSM), then tested for mildew resistance and accelerated aging experiments to evaluate the anti-mildew effect, mechanical strengthening properties and durability of CNCS/PHMG compound solution on ancient books. The results showed the mechanical properties of the paper treated by CNCS/PHMG were significantly improved at the optimum ratio (0.3 wt%:0.3 wt%), with the folding endurance increased by 1.78 times and the increase ratio of tensile strain was 46.62%. Meanwhile, the treated paper maintained the same good zero-span tensile strength after aging 7 days as the sample unaged untreated, indicating superior aging resistance of this treatment method. In addition, excellent biocidal activity with the growth trace of mold less than 10% was observed on treated paper. In conclusion, it is a method that simple to operate, which can be a promising treatment of conservation and enhancement of ancient paper.

Using biopolymers to strengthen the historical printed paper: mechanical and optical characters

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wafika Noshy ◽  
Rushdya Rabee Ali Hassan ◽  
Nada Mohammed
Keyword(s):  
Mechanical Properties ◽  
Design Methodology ◽  
Hydroxypropyl Methylcellulose ◽  
Accelerated Aging ◽  
Hydroxyethyl Cellulose ◽  
Content Type ◽  
Oxidation Processes ◽  
Color Changes ◽  
Dramatic Difference ◽  
Historical Samples

Purpose This study aims to restore the lost mechanical properties of the prints with carrageenan, methyl hydroxyethyl cellulose (Tylose) and hydroxypropyl methylcellulose (Methocel). Design/methodology/approach The effect of these materials on the properties of the printed paper (modern and historical samples) has been evaluated under the influence of accelerated aging using pH measurement, the mechanical properties (tensile and elongation), FTIR and color changes. Findings The three consolidates reduced the acidity of treated samples significantly, but after ageing, it was observed that the pH of aged treated samples decreased slightly as compared to the untreated samples. The results of the mechanical properties showed the superiority of hydroxypropyl methylcellulose (Methocel) in improving the tensile and elongation forces of the samples compared to carrageenan and methyl hydroxyethyl cellulose even during the accelerated aging. Consolidation materials succeeded in reducing ΔE of the paper samples under accelerated aging, especially carrageenan. The IR spectra confirmed that no dramatic difference was observed in topically function vibrations of samples after treatment beside that the O-H stretching band intensity increased observably after treatment with the three consolidates, after ageing the treatment, and it protected the treated paper from oxidation processes as the infrared spectrum analysis showed a decrease in intensities of carbonyl and carboxyl groups as compared to aged untreated samples. Originality/value The research provides new biopolymers in strengthening the historical printed paper, where printed papers lack studies related to their conservation. This makes the current study a promising step for treating historical printed paper.

Investigating the effect of the aging process on LDPE composites with UV protective additives

2020 ◽  
pp. 089270572094190
Author(s):  
Sabih Ovalı ◽  
Erhan Sancak
Keyword(s):  
Mechanical Properties ◽  
Composite Structures ◽  
Color Change ◽  
Accelerated Aging ◽  
Physical And Mechanical Properties ◽  
Ultraviolet Rays ◽  
Color Changes ◽  
Matrix Production ◽  
Ldpe Composites ◽  
Harmful Effects

The contact with ultraviolet rays coming from sunlight causes color changes and deterioration in the main chain structures of composites in outdoor applications and affects the physical and mechanical properties of composite materials negatively. Photodegradation can be slowed and the mechanical strength of composite structures can be improved with adding photostabilizers in polymer matrix production. In this study, we modified low-density polyethylene (LDPE) polymer with an amine light stabilizer (Chimassorb 944), a light absorbent (Tinuvin 326), and an antioxidant (Irganox 1010) and then reinforced with jute fabric (JF). We examined the effect of protective additives, which are used to reduce the harmful effects of sunlight, on JF-reinforced LDPE composites. The color change, physical, and mechanical properties of the composites were determined after 120- and 240-h accelerated aging processes. The results indicate that both the antioxidants and the amine light stabilizers were more effective photostabilizers for JF-reinforced LDPE composites than the absorbents.

scholarly journals Effect of Accelerated Aging on Some Mechanical Properties and Wear of Different Commercial Dental Resin Composites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2769
Author(s):  
Jonne Oja ◽  
Lippo Lassila ◽  
Pekka K. Vallittu ◽  
Sufyan Garoushi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Accelerated Aging ◽  
Wear Depth ◽  
Resin Composites ◽  
Expiration Date ◽  
Dental Resin ◽  
Hydrothermal Aging ◽  
Dental Resin Composites

The aim of current in vitro research was to determine the effect of hydrothermal accelerated aging on the mechanical properties and wear of different commercial dental resin composites (RCs). In addition, the effect of expiration date of the composite prior its use was also evaluated. Five commercially available RCs were studied: Conventional RCs (Filtek Supreme XTE, G-aenial Posterior, Denfil, and >3y expired Supreme XTE), bulk-fill RC (Filtek Bulk Fill), and short fiber-reinforced RC (everX Posterior). Three-point flexural test was used for determination of ultimate flexural strength (n = 8). A vickers indenter was used for testing surface microhardness. A wear test was conducted with 15,000 chewing cycles using a dual-axis chewing simulator. Wear pattern was analyzed by a three-dimensional (3D) noncontact optical profilometer. Degree of C=C bond conversion of monomers was determined by FTIR-spectrometry. The specimens were either dry stored for 48 h (37 °C) or boiled (100 °C) for 16 h before testing. Scanning electron microscopy (SEM) was used to evaluate the microstructure of each material. Data were analyzed using ANOVA (p = 0.05). Hydrothermal aging had no significant effects on the surface wear and microhardness of tested RCs (p > 0.05). While flexural strength significantly decreased after aging (p < 0.05), except for G-aenial Posterior, which showed no differences. The lowest average wear depth was found for Filtek Bulk Fill (29 µm) (p < 0.05), while everX Posterior and Denfil showed the highest wear depth values (40, 39 µm) in both conditions. Passing the expiration date for 40 months did not affect the flexural strength and wear of tested RC. SEM demonstrated a significant number of small pits on Denfil’s surface after aging. It was concluded that the effect of accelerated aging may have caused certain weakening of the RC of some brands, whereas no effect was found with one brand of RC. Thus, the accelerated aging appeared to be more dependent on material and tested material property.

scholarly journals Post-Processing Time Dependence of Shrinkage and Mechanical Properties of Injection-Molded Polypropylene

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 22
Author(s):  
Artur Kościuszko ◽  
Dawid Marciniak ◽  
Dariusz Sykutera
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Injection Molding ◽  
Accelerated Aging ◽  
Mold Temperature ◽  
Degree Of Crystallinity ◽  
Injection Mold ◽  
Secondary Crystallization ◽  
Scanning Calorimetry ◽  
Injection Molded

Dimensions of the injection-molded semi-crystalline materials (polymeric products) decrease with the time that elapses from their formation. The post-molding shrinkage is an effect of secondary crystallization; the increase in the degree of polymer crystallinity leads to an increase in stiffness and decrease in impact strength of the polymer material. The aim of this study was to assess the changes in the values of post-molding shrinkage of polypropylene produced by injection molding at two different temperatures of the mold (20 °C and 80 °C), and conditioned for 504 h at 23 °C. Subsequently, the samples were annealed for 24 h at 140 °C in order to conduct their accelerated aging. The results of shrinkage tests were related to the changes of mechanical properties that accompany the secondary crystallization. The degree of crystallinity of the conditioned samples was determined by means of density measurements and differential scanning calorimetry. It was found that the changes in the length of the moldings that took place after removal from the injection mold were accompanied by an increase of 20% in the modulus of elasticity, regardless of the conditions under which the samples were made. The differences in the shrinkage and mechanical properties of the samples resulting from mold temperature, as determined by tensile test, were removed by annealing. However, the samples made at two different injection mold temperature values still significantly differed in impact strength, the values of which were clearly higher for the annealed samples compared to the results determined for the samples immediately after the injection molding.

scholarly journals Effects of surface defects on the mechanical properties of ZnO nanowires

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Aditi Roy ◽  
James Mead ◽  
Shiliang Wang ◽  
Han Huang
Keyword(s):  
Mechanical Properties ◽  
Surface Defects ◽  
Zno Nanowires

scholarly journals INTEMPERISMO ARTIFICIAL DE QUATRO REVESTIMENTOS APLICADOS EM MADEIRAS DE DUAS ESPÉCIES FLORESTAIS

Nativa ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 313 ◽  
Author(s):  
Aline Krolow Soares ◽  
Roberto Lessa Pereira ◽  
Pedro Henrique Gonzalez de Cademartori ◽  
Henrique Weber Dalla Costa ◽  
Darci Alberto Gatto
Keyword(s):  
Morphological Changes ◽  
Eucalyptus Grandis ◽  
Accelerated Aging ◽  
Surface Wettability ◽  
Forest Species ◽  
Artificial Weathering ◽  
Color Changes ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Weathering Resistance

O presente estudo teve como objetivo investigar a resistência ao intemperismo artificial de quatro revestimentos aplicados nas madeiras de duas espécies florestais. Para tal, foram utilizadas seis árvores de Eucalyptus grandis e três árvores de Tetrorchidium rubrivenium as quais foram desdobradas para confecção de 50 amostras para cada espécie, com dimensões de 5,0x7,0x1,0cm (largura, comprimento e espessura, respectivamente). A superfície das madeiras foi revestida com quatro acabamentos: polistein, verniz marítimo, tinta branca base óleo e tinta branca base água. As amostras sem revestimento e revestidas foram submetidas ao ensaio de envelhecimento acelerado durante 480 horas. A resistência ao intemperismo artificial foi avaliada por meio das modificações colorimétricas e morfológicas ao longo da exposição das madeiras e em função da molhabilidade superficial. Os principais resultados mostraram que a superfície das madeiras  tendeu a tons opacos após exposição de 480 horas. Foi observado que os revestimentos não evitaram o aumento da molhabilidade superficial. Após todo o período de exposição, as madeiras não apresentaram modificações morfológicas tais como rachaduras e descascamento dos revestimentos, o que denota importante característica de proteção à madeira.Palavras-chave: Eucalyptus, canemaçu, modificação da superfície, envelhecimento acelerado, durabilidade da madeira. ARTIFICIAL WEATHERING OF FOUR COATINGS APPLIED ON WOODS OF TWO FOREST SPECIES ABSTRACT:The present study aimed to investigate the resistance to artificial weathering of four coatings applied on wood from two forest species. Six trees of Eucalyptus grandis and three trees of Tetrorchidium rubrivenium were cut to produce 50 wood samples for each species with dimensions of 5.0x7.0x1.0 cm (width, length and thickness, respectively). Wood surface was coated with four finishing products: polistein, marine varnish, oil-based white paint and water-based white paint. The uncoated and coated wood samples were subjected to accelerated aging test for 480h. The artificial weathering resistance was evaluated by color changes and surface wettability. The main results showed the coated woods tend to opaque tones after the exposure for 480h. The coatings did not avoid the increase of the surface wettability. After the exposure, both woods did not present morphological changes, such as cracks and peeling into the coatings, which represent relevant characteristics for wood protection.Keywords: Eucalyptus, canemaçu, surface modification, accelerated aging, wood durability. DOI:

scholarly journals Continuous Blown Film Preparation of High Starch Content Composite Films with High Ultraviolet Aging Resistance and Excellent Mechanical Properties

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3813
Author(s):  
Bowen Lin ◽  
Chengqiang Li ◽  
Fangping Chen ◽  
Changsheng Liu
Keyword(s):  
Mechanical Properties ◽  
Lignin Content ◽  
Starch Content ◽  
Composite Films ◽  
Oh Groups ◽  
Longitudinal Tensile Strength ◽  
High Starch Content ◽  
Aging Resistance ◽  
High Starch ◽  
Ultraviolet Aging

Starch/PBAT blown films with high ultraviolet aging resistance and excellent mechanical properties were prepared by introducing lignin with polyurethane prepolymer (PUP) as a starch modifier and physical compatibilizer and 4,4′–methylene diphenyl diisocyanate (MDI) as a crosslinker. Starch was modified by reacting the NCO groups of the PUP with the OH groups of the starch to form a carbamate bond. The mechanical properties, hydrophobic properties, ultraviolet barrier, ultraviolet aging properties and microscopic morphology of starch/PBAT films with different contents of lignin were investigated. The results showed that the starch/PBAT films were blown continuously. The addition of lignin did not decrease the mechanical properties. On the contrary, the film with 1% lignin possessed the excellent mechanical properties with longitudinal tensile strength of 15.87 MPa and the elongation at a break of 602.21%. In addition, the higher the lignin content, the better the UV blocking effect. The introduction of lignin did not affect the crystalline properties but improved the hydrophilic properties and sealing strength of the high starch content composite films.

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