Extensional rheology of raw natural rubber from new clones of <i>Hevea brasiliensis</i>

Lotti, Cybele; Moreno, R. M. B.; Gonçalves, Paulo de Souza; Bhattacharya, S. N.; Mattoso, Luiz H. C.

doi:10.1002/pen.22056

Cited by 7 publications

(2 citation statements)

References 23 publications

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“…Figure 5 shows the TG analysis coupled to FTIR for the NR (a), NR/KSN with 10 phr (b) and NR/NZF with 10 phr (c). As expected, all the spectra exhibit all of the vibration band characteristics of the poly(cis-1,4-isoprene) structure [25,26]. It is possible to identify the presence of two main sets of bonds indicated by red arrows.…”

Section: Resultssupporting

confidence: 75%

Evolution of thermal properties of natural rubber nanocomposites functionalized by nickel–zinc ferrite and potassium strontium niobate nanopowders

Bellucci

Almeida

Agostini

et al. 2016

J Therm Anal Calorim

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Several composites and nanocomposites based on a polymeric matrix and ceramic fillers are being pursued for use as multifunctional and innovative materials. Nevertheless, there is a series of challenges to be solved in this area such as the understanding of the role of interfaces and the synergy between matrix and fillers. In this work, vulcanized natural rubber nanocomposites were prepared with different concentrations of two kinds of ceramic nanoparticles, potassium strontium niobate (KSr 2 Nb 5 O 15 or KSN) and nickel-zinc ferrite (Ni 0.5 Zn 0.5 Fe 2 O 4 or NZF), synthesized by a chemical method known as the modified polyol method. Morphological and thermal characterizations were carried out by AFM, TG/DTG, TG/FTIR and DSC. The thermal properties of nanocomposites were compared and discussed as functions of concentration, type and surface of nanoparticles. The results obtained suggest that the base concentration for both types of nanoparticles inside the polymer matrix volume greatly adds to the increase in thermal stability up to 11 % and the glass transition temperature up to 10°C. A similar evolution for the glass transition temperature (T g), thermal stability temperature (T S) and dielectric permittivity (e 0) was identified, suggesting that these phenomena are mainly dominated by the same mechanisms. These results point to the possibility for the thermal parameter modulation in magnetic and ferroelectric nanocomposites by means of a suitable control of concentration and properties of the KSN and NZF nanoparticles. Keywords Nickel-zinc ferrite Á Potassium strontium niobate Á Functionalized nanocomposites Á Thermal properties Á Thermal stability Á Glass transition temperature & Aldo Eloizo Job

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Section: Resultssupporting

confidence: 75%

Evolution of thermal properties of natural rubber nanocomposites functionalized by nickel–zinc ferrite and potassium strontium niobate nanopowders

Bellucci

Almeida

Agostini

et al. 2016

J Therm Anal Calorim

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“…A similar reduction in mechanical properties was observed for MRNR. In the latter case, we suggest that the observed effect could result from two opposite trends: as the rubber particle membrane is essentially composed of phospholipids and proteins [14]; its efficient removal induces fewer branch points at chain ends. This is verified by the N% ( Table 5).…”

Section: Mechanical Propertiesmentioning

confidence: 87%

Effect of Non-Rubber Constituents on Guayule and Hevea Rubber Intrinsic Properties

Monadjemi

McMahan

Cornish

2016

J. Res. Updates Polym. Sci.

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To meet the increasing demand for natural rubber (NR), currently sourced from the tropical rubber tree Hevea brasiliensis, and address price volatility and steadily increasing labor costs, alternate rubber-producing species are in commercial development. One of these, guayule (Parthenium argentatum), has emerged on the market as a commercial source of high quality rubber. Non-rubber constituents play an important role in the physical properties of NR products. The intrinsic composition of the two NR materials differs and these differences may be a principal cause of the performance differences between them. We have compared the effect of non-rubber constituents, such as protein, lipids, resin and rubber particle membranes. Firstly, a film casting method was developed to obtain rubber films with a uniform thickness. Secondly, the glass transition temperature of different rubbers was determined by dynamic mechanical analysis, and tensile properties were tested for uncompounded materials. Guayule natural rubber (GNR), from which most of the membranes were removed while in latex form (MRGNR) was found to have higher intrinsic strength than GNR or gel-free NR (FNR). An acetone extraction was performed to quantify the resin and free lipids in the rubber samples.

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Rubber yield prediction by meteorological conditions using mixed models and multi-model inference techniques

et al. 2015

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Linear mixed models were developed and used to predict rubber (Hevea brasiliensis) yield based on meteorological conditions to which rubber trees had been exposed for periods ranging from 1 day to 2 months prior to tapping events. Predictors included a range of moving averages of meteorological covariates spanning different windows of time before the date of the tapping events. Serial autocorrelation in the latex yield measurements was accounted for using random effects and a spatial generalization of the autoregressive error covariance structure suited to data sampled at irregular time intervals. Information theoretics, specifically the Akaike information criterion (AIC), AIC corrected for small sample size (AICc), and Akaike weights, was used to select models with the greatest strength of support in the data from a set of competing candidate models. The predictive performance of the selected best model was evaluated using both leave-one-out cross-validation (LOOCV) and an independent test set. Moving averages of precipitation, minimum and maximum temperature, and maximum relative humidity with a 30-day lead period were identified as the best yield predictors. Prediction accuracy expressed in terms of the percentage of predictions within a measurement error of 5 g for cross-validation and also for the test dataset was above 99 %.

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Extensional rheology of raw natural rubber from new clones of Hevea brasiliensis

Cited by 7 publications

References 23 publications

Evolution of thermal properties of natural rubber nanocomposites functionalized by nickel–zinc ferrite and potassium strontium niobate nanopowders

Evolution of thermal properties of natural rubber nanocomposites functionalized by nickel–zinc ferrite and potassium strontium niobate nanopowders

Effect of Non-Rubber Constituents on Guayule and Hevea Rubber Intrinsic Properties

Rubber yield prediction by meteorological conditions using mixed models and multi-model inference techniques

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