scholarly journals Structural Features and Properties’ Characterization of Polylactic Acid/Natural Rubber Blends with Epoxidized Soybean Oil

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1101
Author(s):  
Andrey Burkov ◽  
Alexander Kraev ◽  
Maxim Grishin ◽  
Roman Vesnin ◽  
Sergey Fomin ◽  
...  

Because of the effort to preserve petroleum resources and promote the development of eco-friendly materials, bio-based polymers produced from sustainable resources have attracted great attention. Among them, polylactide (PLA) and natural rubber (NR) present prominent polymers with unique barrier and mechanical features. A series of samples with improved phase compatibility were obtained by blending PLA and NR using a double-rotor mixer. A plasticizing and enhancing effect on the polymers’ compatibility was achieved by using epoxidized soybean oil (ESO) as a natural plasticizer and compatibilizer. ESO compounding in the PLA-NR blends increased the mobility of the biopolymer’s molecular chains and improved the thermal stability of the novel material. The size of the NR domains embedded in the continuous PLA matrix decreased with the ESO content increment. The combination of thermal analysis and scanning electron microscopy enabled the authors to determine the features of potential packaging material and the optimal content of PLA-NR-ESO for the best mechanical properties.


2021 ◽  
pp. 009524432110386
Author(s):  
Camila Taliotto Scarton ◽  
Nayrim Brizuela Guerra ◽  
Marcelo Giovanela ◽  
Suélen Moresco ◽  
Janaina da Silva Crespo

In the tire industry, the incorporation of natural origin oils in the development of elastomeric formulations has been one of the alternatives to reduce the use of petroleum derivatives, with a high content of toxic compounds. In this work, soybean vegetable oil was investigated as a lubricant and co-activator in sulfur-vulcanized natural rubber compounds. The soybean oil was used in its natural state and chemically modified by the epoxy ring’s introduction in its structure. In an internal mixer a standard formulation of natural rubber, five formulations replacing a conventional aromatic oil and stearic acid by vegetable oil, and a formulation without an activation system were prepared. The natural and epoxidized soybean oil was characterized chemically, and the elastomeric compositions were evaluated by mechanical and rheological analysis. The mechanical properties showed satisfactory results when vegetable soybean oil was used as a lubricant and could be a substitute for conventional aromatic oils, thus guaranteeing reduction of aromatic polycyclic content in the formulations. The crosslink degree and the rheological characteristics of the samples prepared with vegetable soybean oil were similar to the natural rubber standard sample. The formulations without the zinc oxide and stearic acid evidenced the need for activators in the vulcanization reaction, as they presented properties below standard. We verified that the epoxidized soybean oil, even when promoting better dispersion of the fillers, interfered in the crosslink formation, and consequently there was a decrease in the mechanical properties of these formulations. Finally, we indicated vegetable soybean oil as a substitute for aromatic oil and stearic acid, in the elastomeric compositions used to manufacture treads.



Robert May's seminal book has played a central role in the development of ecological science. Originally published in 1976, this influential text has overseen the transition of ecology from an observational and descriptive subject to one with a solid conceptual core. Indeed, it is a testament to its influence that a great deal of the novel material presented in the earlier editions has now been incorporated into standard undergraduate textbooks. It is now a quarter of a century since the publication of the second edition, and a thorough revision is timely. Theoretical Ecology provides a succinct, up-to-date overview of the field set in the context of applications, thereby bridging the traditional division of theory and practice. It describes the recent advances in our understanding of how interacting populations of plants and animals change over time and space, in response to natural or human-created disturbance. In an integrated way, initial chapters give an account of the basic principles governing the structure, function, and temporal and spatial dynamics of populations and communities of plants and animals. Later chapters outline applications of these ideas to practical issues including fisheries, infectious diseases, tomorrow's food supplies, climate change, and conservation biology. Throughout the book, emphasis is placed on questions which as yet remain unanswered. The editors have invited the top scientists in the field to collaborate with the next generation of theoretical ecologists. The result is an accessible, advanced textbook suitable for senior undergraduate and graduate level students as well as researchers in the fields of ecology, mathematical biology, environmental and resources management. It will also be of interest to the general reader seeking a better understanding of a range of global environmental problems.



2012 ◽  
Vol 89 (11) ◽  
pp. 2067-2075 ◽  
Author(s):  
J. M. España ◽  
L. Sánchez-Nacher ◽  
T. Boronat ◽  
V. Fombuena ◽  
R. Balart


Author(s):  
Tian Liang ◽  
Avraam I. Isayev ◽  
Shuailin Zhang ◽  
Stephen Z. D. Cheng


Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1510
Author(s):  
Marek Pöschl ◽  
Shibulal Gopi Sathi ◽  
Radek Stoček ◽  
Ondřej Kratina

The rheometer curing curves of neat natural rubber (NR) and neat chloroprene rubber (CR) with maleide F (MF) exhibit considerable crosslinking torque at 180 °C. This indicates that MF can crosslink both these rubbers via Alder-ene reactions. Based on this knowledge, MF has been introduced as a co-crosslinking agent for a 50/50 blend of NR and CR in conjunction with accelerated sulfur. The delta (Δ) torque obtained from the curing curves of a blend with the addition of 1 phr MF was around 62% higher than those without MF. As the content of MF increased to 3 phr, the Δ torque was further raised to 236%. Moreover, the mechanical properties, particularly the tensile strength of the blend with the addition of 1 phr MF in conjunction with the accelerated sulfur, was around 201% higher than the blend without MF. The overall tensile properties of the blends cured with MF were almost retained even after ageing the samples at 70 °C for 72 h. This significant improvement in the curing torque and the tensile properties of the blends indicates that MF can co-crosslink between NR and CR via the Diels–Alder reaction.





2021 ◽  
pp. 009524432110290
Author(s):  
Leandro Hernán Esposito ◽  
Angel José Marzocca

The potential replacement of a treated residual aromatic extract mineral oil (TRAE) by a highly epoxidized soybean oil (ESO) into a silica-filled styrene-butadiene rubber compound was investigated. In order to determine if ESO compounds performance are suitable for tread tire applications, processing properties cure and characteristics were evaluated. The impact of ESO amount on the silica dispersion was confirmed by Payne Effect. The presence of chemical or physical interactions between ESO and silica improves the filler dispersion, enabling the compound processability and affecting the cure kinetic rate. An adjusted rubber compound with 2 phr of ESO and 2 phr of sulfur presented the higher stiffness and strength values with lower weight loss from a wear test compared with TRAE compound at an equal amount of oil and curing package. Furthermore, wet grip and rolling resistance predictors of both compounds gave comparable results, maintaining a better performance and reducing the dependence of mineral oil for tire tread compounds.



Author(s):  
Meihong Liu ◽  
Shaoyi Lyu ◽  
Limin Peng ◽  
Liping Cai ◽  
Zhenhua Huang ◽  
...  


Author(s):  
Arkadiusz Zych ◽  
Jonathan Tellers ◽  
Laura Bertolacci ◽  
Luca Ceseracciu ◽  
Lara Marini ◽  
...  


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