High molar mass silicone rubber reinforced with montmorillonite clay masterbatches: Morphology and mechanical properties

2010 ◽  
Vol 46 (5) ◽  
pp. 881-890 ◽  
Author(s):  
Manuela L.Q.A. Kaneko ◽  
Rafaelle Bonzanini Romero ◽  
Maria do Carmo Gonçalves ◽  
Inez V.P. Yoshida
e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Veronika Rabova ◽  
Petr Hron

AbstractThe effect of surface modified fillers based on montmorillonite on rheological and mechanical properties and thermal stability of high-molar mass polydimethylsiloxane matrix was evaluated. Silicone rubber/clay composites were prepared via homogenisation on open two roll-mill followed by torque measurement at two different temperatures. At 30 °C and 100 °C the torque did not extremely differ excepting the mixtures containing Cloisite 15A where it achieved the maximum at 3 phr montmorillonite content, but the tensile strength reached the similar values in all mixtures. Thermogravimetric analysis was utilized to find out the differences in weight decay of composites in silicone rubber/montmorillonite mixtures and in unfilled silicone rubber. Synergism of fillers was also studied and led to tensile strength increase.


2021 ◽  
Author(s):  
Wenhuan Zhang ◽  
Zhaoping Deng ◽  
Hongwei Yuan ◽  
Shikai Luo ◽  
Huayin Wen ◽  
...  

AbstractIn this paper, silicone rubber materials with foam/solid alternating multilayered structures were successfully constructed by combining the two methods of multilayered hot-pressing and supercritical carbon dioxide (SCCO2) foaming. The cellular morphology and mechanical properties of the foam/solid alternating multilayered silicone rubber materials were systematically studied. The results show that the growth of the cell was restrained by the solid layer, resulting in a decrease in the cell size. In addition, the introduction of the solid layer effectively improved the mechanical properties of the microcellular silicone rubber foam. The tensile strength and compressive strength of the foam/solid alternating multilayered silicone rubber materials reached 5.39 and 1.08 MPa, which are 46.1% and 237.5% of the pure silicone rubber foam, respectively. Finite element analysis (FEA) was applied and the results indicate that the strength and proportion of the solid layer played important roles in the tensile strength of the foam/solid alternating multilayered silicone rubber materials. Moreover, the small cellular structures in silicone rubber foam can provided a high supporting counterforce during compression, meaning that the microcellular structure of silicone rubber foam improved the compressive property compared to that for the large cellular structure of silicone rubber foam.


2012 ◽  
Vol 624 ◽  
pp. 256-259 ◽  
Author(s):  
Zhen Wu ◽  
Ying Qiang Zhang ◽  
Qing Guo

In this paper the mobility and factots affecting mobility of phenyl silicone rubber is studied. The results showed that the crystallinity of phenyl silicone rubber was declined because of the presence of phenyl and the higher the phenyl content, the lower the crystallinity when the phenyl content was low. The viscosity of the phenyl silicone rubber was rised as molar mass and phenyl content of the rubber was increased but the changes was not uniform. The viscosity of the phenyl silicone rubber was declined as temperature was increased and viscosity-temperature dependence of the high molar mass phenyl silicone rubber was larger. The influence of shearing on the viscosity and mobility of the phenyl silicone rubber were evident.


2020 ◽  
Vol 11 ◽  
pp. 204173142095431
Author(s):  
Shubham Jain ◽  
Mohammed Ahmad Yassin ◽  
Tiziana Fuoco ◽  
Hailong Liu ◽  
Samih Mohamed-Ahmed ◽  
...  

We present a solution to regenerate adipose tissue using degradable, soft, pliable 3D-printed scaffolds made of a medical-grade copolymer coated with polydopamine. The problem today is that while printing, the medical grade copolyesters degrade and the scaffolds become very stiff and brittle, being not optimal for adipose tissue defects. Herein, we have used high molar mass poly(L-lactide-co-trimethylene carbonate) (PLATMC) to engineer scaffolds using a direct extrusion-based 3D printer, the 3D Bioplotter®. Our approach was first focused on how the printing influences the polymer and scaffold’s mechanical properties, then on exploring different printing designs and, in the end, on assessing surface functionalization. Finite element analysis revealed that scaffold’s mechanical properties vary according to the gradual degradation of the polymer as a consequence of the molar mass decrease during printing. Considering this, we defined optimal printing parameters to minimize material’s degradation and printed scaffolds with different designs. We subsequently functionalized one scaffold design with polydopamine coating and conducted in vitro cell studies. Results showed that polydopamine augmented stem cell proliferation and adipogenic differentiation owing to increased surface hydrophilicity. Thus, the present research show that the medical grade PLATMC based scaffolds are a potential candidate towards the development of implantable, resorbable, medical devices for adipose tissue regeneration.


2010 ◽  
Vol 25 (3) ◽  
pp. 310-318 ◽  
Author(s):  
Tero Taipale ◽  
Janne Laine ◽  
Susanna Holappa ◽  
Jonni Ahlgren ◽  
Juan Cecchini

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 628
Author(s):  
Adolfo Benedito ◽  
Eider Acarreta ◽  
Enrique Giménez

The present paper describes a greener sustainable route toward the synthesis of NIPHUs. We report a highly efficient solvent-free process to produce [4,4′-bi(1,3-dioxolane)]-2,2′-dione (BDC), involving CO2, as renewable feedstock, and bis-epoxide (1,3-butadiendiepoxide) using only metal–organic frameworks (MOFs) as catalysts and cetyltrimethyl-ammonium bromide (CTAB) as a co-catalyst. This synthetic procedure is evaluated in the context of reducing global emissions of waste CO2 and converting CO2 into useful chemical feedstocks. The reaction was carried out in a pressurized reactor at pressures of 30 bars and controlled temperatures of around 120–130 °C. This study examines how reaction parameters such as catalyst used, temperature, or reaction time can influence the molar mass, yield, or reactivity of BDC. High BDC reactivity is essential for producing high molar mass linear non-isocyanate polyhydroxyurethane (NIPHU) via melt-phase polyaddition with aliphatic diamines. The optimized Al-OH-fumarate catalyst system described in this paper exhibited a 78% GC-MS conversion for the desired cyclic carbonates, in the absence of a solvent and a 50 wt % chemically fixed CO2. The cycloaddition reaction could also be carried out in the absence of CTAB, although lower cyclic carbonate yields were observed.


2021 ◽  
pp. 2100186
Author(s):  
Annelore Aerts ◽  
Camiel Kroonen ◽  
Jan Henk Kamps ◽  
Rint P. Sijbesma ◽  
Johan P. A. Heuts

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