Thermoreversible Crosslinking Rubber Using Supramolecular Hydrogen Bonding Networks

2002 ◽  
Vol 75 (4) ◽  
pp. 713-723 ◽  
Author(s):  
Keisuke Chino ◽  
Makoto Ashiura ◽  
Junichiro Natori ◽  
Masahiro Ikawa ◽  
Tetsuji Kawazura
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Bonding ◽  
Solid Phase ◽  
Thermoplastic Elastomers ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Vulcanized Rubber ◽  
Superior Mechanical Properties ◽  
Hydrogen Bonding Networks ◽  
Isoprene Rubber

Abstract Thermoreversible crosslinking rubber (TRC-IR) was easily synthesized by modification of isoprene rubber (IR) with maleic anhydride followed by the addition of 3-amino-1,2,4-triazole (ATA), in solid phase. The mechanical properties of the resulting rubber were more similar to the sulfur-vulcanized rubber than general thermoplastic elastomers (ex. SEBS). Although the tensile strength and elongation at break were lower than those of a corresponding sulfur-vulcanized rubber, the moduli were as high as those of sulfur-cured rubber. Re-molding of TRC-IR could be repeated more than 10 times without significantly changing its mechanical properties. Differential scanning calorimetry (DSC) and infrared analyses revealed that the superior mechanical properties and good recyclability are attributable to the strong hydrogen bonding. The TRC-IR showed an endothermic transition peak at around 185 °C on the DSC chart, indicating cleavage of the hydrogen bonding. Infrared analyses also revealed that the absorption peaks of carboxylic acid were shifted to a lower region by the strong hydrogen bonding. The thermoreversible crosslinking system was also applied to EPM, EBM (ethylene-butene rubber), and IIR. These rubbers also showed superior mechanical properties as well as excellent recyclability.

Effects of walnut shell powders on the morphology and the thermal and mechanical properties of poly(lactic acid)

2019 ◽  
Vol 33 (10) ◽  
pp. 1383-1395
Author(s):  
Hongjuan Zheng ◽  
Zhengqian Sun ◽  
Hongjuan Zhang
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Property Testing ◽  
Walnut Shell ◽  
Poly Lactic Acid ◽  
Thermal And Mechanical Properties ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Heat Distortion Temperature ◽  
Testing Techniques

Poly(lactic acid) (PLA) has good environmental compatibility, however, its high brittleness, slow rate of crystallization, and low heat distortion temperature restrict its widespread use. To overcome these limitations, in this study, PLA was mixed with walnut shell (WS) powders. The effects of WS powders on the morphology and the thermal and mechanical properties of PLA were investigated. The products were characterized by differential scanning calorimetry (DSC), infrared (IR) spectroscopy, polarizing optical microscopy (POM), and various mechanical property testing techniques. The results showed that WS powders had a significant effect on the morphology and the thermal and mechanical properties of PLA. The tensile strength, impact strength, and elongation at break of the PLA/WS composites first increased and then decreased with the increasing addition of WS powders. When the addition of WS powders was about 0.5 wt%, they reached maximum values of 51.2 MPa, 23.3 MPa, and 19.0%, respectively. Compared with neat PLA, the spherulite grain size of the composites could be reduced and many irregular polygons were formed during crystallization. The melting, cold crystallization, and glass-transition temperatures of the composites were lower than those of neat PLA.

Mechanochemical Devulcanization of Vulcanized Gum Natural Rubber

2005 ◽  
Vol 21 (3) ◽  
pp. 183-199
Author(s):  
G.K. Jana ◽  
C.K. Das
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Three Dimensional ◽  
Elongation At Break ◽  
Tear Strength ◽  
Vulcanized Rubber ◽  
Dimensional Network ◽  
Polymeric Chains ◽  
Cure Time

De-vulcanization of vulcanized elastomers represents a great challenge because of their three-dimensional network structure. Sulfur-cured gum natural rubbers containing three different sulfur/accelerator ratios were de-vulcanized by thio-acids. The process was carried out at 90 °C for 10 minutes in an open two-roll cracker-cum-mixing mill. Two concentrations of de-vulcanizing agent were tried in order to study the cleavage of the sulfidic bonds. The mechanical properties of the re-vulcanized rubber (like tensile strength, modulus, tear strength and elongation at break) were improved with increasing concentrations of de-vulcanizing agent, because the crosslink density increased. A decrease in scorch time and in optimum cure time and an increase in the state of cure were observed when vulcanized rubber was treated with high amounts of de-vulcanizing agent. The temperature of onset of degradation was also increased with increasing concentration of thio-acid. DMA analysis revealed that the storage modulus increased on re-vulcanization. From IR spectroscopy it was observed that oxidation of the main polymeric chains did not occur at the time of high temperature milling. Over 80% retention of the original mechanical properties (like tensile strength, modulus, tear strength and elongation at break) of the vulcanized natural rubber was achieved by this mechanochemical process.

scholarly journals PREPARATION AND CHARACTERIZATIONS OF LATEX/FILLER NANOCOMPOSITES

2020 ◽  
Vol 21 (2) ◽  
pp. 230-238
Author(s):  
Mohamad Firdaus Omar ◽  
NURIAH MOHAMAD ◽  
Fathilah Ali
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Coupling Agent ◽  
Morphological Properties ◽  
Rubber Matrix ◽  
Silane Coupling Agents ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Silane Coupling ◽  
Latex Compounding

Latex compounding which incorporates various types of clays as filler to the rubber can significantly give reinforcement in the rubber matrix when rubber/clay nanocomposites are formed, but the filler agglomerates. Thus, study was conducted by using Kaolin clay as the filler in the rubber nanocomposites with silane coupling agent to functionalize the surface of the filler. This study was done in order to investigate the mechanical properties of various functionalized Kaolin in latex nanocomposites, to prepare various ratios of Kaolin to rubber, and to characterize mechanical, thermal and morphological properties of the Kaolin in latex nanocomposites. To achieve these, six types of silane coupling agents was used for Kaolin filler surface functionalization purpose during the filler’s incorporation in latex compounding. The optimized coupling agent, USi-7301 (?-chloropropyltrimetoxysilane) – with tensile strength value of 32.77 MPa, elongation at break value of 632.589 % and force at break value of 6.737 N – was used to further functionalize Kaolin filler in different ratios so as to achieve the optimum mechanical, thermal and morphological properties of the filler in the polymer matrix. Universal tensile machine was used to analyze the mechanical properties of the nanocomposites, while the Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC) were used to observe the morphological and thermal properties of the nanocomposites, respectively. The results showed that reducing the Total Solids Content (TSC) of Kaolin filler to 26 % somehow showed the optimized properties of the nanocomposites, giving 34.00 MPa tensile strength, 576.494 % elongation at break and 6.564 N force at break. Rough surface morphology was observed under SEM suggesting the occurrence of phase separation between the hydrophilic filler and the hydrophobic rubber matrix. In the DSC plot, sample with USi-7301 and with functionalized Kaolin filler 26 % TSC showed glass transition temperature shifted to lower region compared to normal nitrile rubber. The reinforcement of nanocomposites formed will not only enhance the properties of the nanocomposites, but is also economically feasible thus brings advantages to the industry. ABSTRAK: Penyebatian lateks yang menggabungkan pelbagai jenis tanah liat sebagai pengisi dalam getah dapat memberi pengukuhan dalam matriks getah dengan ketara apabila nanokomposit getah / tanah liat terbentuk, tetapi pengisi mengagregat. Oleh itu, kajian dijalankan dengan menggunakan tanah liat Kaolin sebagai pengisi dalam nanokomposit getah dengan ejen gandingan silan untuk menambah-fungsi permukaan pengisi tersebut. Kajian ini dilakukan untuk mengenalpasti sifat mekanik pelbagai Kaolin (yang berfungsi) dalam nanokomposit lateks, untuk menyediakan pelbagai nisbah Kaolin terhadap getah, dan untuk mencirikan sifat mekanik, haba dan morfologi Kaolin dalam nanokomposit lateks. Untuk mencapainya, enam jenis ejen gandingan silan digunakan untuk tujuan menambah-fungsi permukaan pengisi Kaolin semasa penggabungan pengisi dalam penyebatian lateks. Ejen gandingan silan yang paling optimum, USi-7301 (?-silan kloropropiltrimetoksi) - dengan nilai kekuatan tegangan 32.77 MPa, nilai pemanjangan ketika pemutusan 632.589% dan kekuatan daya ketika pemutusan 6.737 N - digunakan dengan lebih lanjut untuk menambah-fungsi pengisi Kaolin dalam nisbah yang berbeza untuk lebih mencapai sifat mekanikal, haba dan morfologi optimum pengisi dalam matriks polimer lateks. Mesin tegangan universal digunakan untuk menganalisis sifat mekanik nanokomposit, sementara Mikroskopi Elektron Pengimbasan (SEM) dan Kalorimetri Pengimbasan Berbeza (DSC) digunakan untuk menganalisa sifat morfologi dan haba nanokomposit tersebut. Hasil kajian menunjukkan bahawa pengurangan Jumlah Kandungan Pepejal (TSC) pengisi Kaolin kepada 26% menunjukkan sifat optimum nanokomposit, dengan kekuatan tegangan 34.00 MPa, pemanjangan ketika pemutusan sebanyak 576.494% dan daya ketika pemutusan sebanyak 6.564 N. Morfologi permukaan kasar diperhatikan di bawah SEM dan ia menunjukkan berlakunya pemisahan fasa antara pengisi hidrofilik dan matriks getah hidrofobik. Dalam plot DSC, sampel dengan USi-7301 dan dengan pengisi Kaolin yang difungsikan dengan 26% TSC menunjukkan suhu peralihan kaca beralih ke kawasan yang lebih rendah berbanding getah nitril biasa. Pengukuhan nanokomposit yang terbentuk bukan sahaja akan meningkatkan sifat nanokomposit, tetapi juga dapat dilaksanakan secara ekonomi sehingga memberi banyak kelebihan kepada industri.

The Effect of Mixed Chain Extender on the Hydrogen Bonding, Thermal and Mechanical Properties of TPUs

2020 ◽  
Vol 1001 ◽  
pp. 16-21
Author(s):  
Ju Jie Sun ◽  
Hai Rui Wang ◽  
Lan Cao ◽  
Tridib K. Sinha
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Hydrogen Bonding ◽  
Thermoplastic Polyurethane ◽  
Chain Extender ◽  
Mixing Ratio ◽  
Thermal And Mechanical Properties ◽  
Elongation At Break ◽  
Chain Extenders ◽  
Hard Block

Chain extender plays a significant role in enhancing the final mechanical properties of thermoplastic polyurethane (TPUs) derived from polytetra methylene etherglycol (PTMG) and 4,4-diphenylmethane diisocyanate (MDI). In this research we focused on the effect that mixed chain extender of ethylene glycol (EG) and 1,4-butanediol (BDO) used has on the phase behavior and morphology of high hard block content TPUs. DSC, FTIR, and mechanical testing were mainly used to characterize the morphology and properties of the TPUs materials. Through this work we were able to show that mixed ratio of different chain extenders had dramatic effects on the properties of the TPUs. After mixing EG and BDO, the degree of hydrogen bonding, melting temperature, tensile strength, tear strength, and hardness of TPUs are all reduced, the glass transition temperature is increased. when the mixing ratio is 1: 1 , the elongation at break is increased to 672% . However, when the mixing ratio is n (EG): n (BDO) = 1: 2, the tensile strength is increased to 29.2 MPa, and the elongation at break is reduced to 353%.

Superior Mechanical Properties of Ultrasonically Recycled EPDM Rubber

2003 ◽  
Vol 76 (1) ◽  
pp. 253-270 ◽  
Author(s):  
Jushik Yun ◽  
A. I. Isayev
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Power Consumption ◽  
Crosslink Density ◽  
Dynamic Properties ◽  
Extensive Study ◽  
Processing Conditions ◽  
Elongation At Break ◽  
Epdm Rubber ◽  
Superior Mechanical Properties

Abstract This paper describes the results of an extensive study involving the continuous ultrasonic devulcanization of unfilled EPDM rubber. Die pressure and ultrasound power consumption were measured as a function of processing conditions. The mechanical properties of aged and fresh revulcanized EPDM rubber were measured. Gel fraction, crosslink density, and dynamic properties were also determined for the virgin vulcanizate, the ultrasonically devulcanized rubber, and the revulcanized rubber. Additionally, the cure behavior of virgin and devulcanized EPDM rubber was investigated. The tensile strength of revulcanized EPDM rubber was found to be much higher than that of the virgin vulcanizate with the elongation at break being practically intact. A mechanism explaining the increase in mechanical properties of revulcanized rubbers was proposed.

Superior Mechanical Properties of Reclaimed SBR with Bimodal Network

1997 ◽  
Vol 70 (2) ◽  
pp. 194-201 ◽  
Author(s):  
A. I. Isayev ◽  
S. H. Kim ◽  
V. Yu Levin
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Crosslink Density ◽  
Processing Conditions ◽  
Elongation At Break ◽  
Gel Fraction ◽  
Superior Mechanical Properties

Abstract The correlation between the mechanical properties of revulcanized SBR, total and polysulfidic crosslink density, gel fraction of original vulcanizate, ultrasonically devulcanized, and revulcanized rubber is described. Under some processing conditions the tensile strength of revulcanized SBR is found to be much higher than that of the original vulcanizate with elongation at break being practically intact. A model explaining the increase in mechanical properties of revulcanized rubber is proposed.

scholarly journals All acrylic-based thermoplastic elastomers with high upper service temperature and superior mechanical properties

2017 ◽  
Vol 8 (37) ◽  
pp. 5741-5748 ◽  
Author(s):  
Wei Lu ◽  
Yangyang Wang ◽  
Weiyu Wang ◽  
Shiwang Cheng ◽  
Jiahua Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermoplastic Elastomers ◽  
Service Temperature ◽  
Superior Mechanical Properties

All acrylic-based thermoplastic elastomers (TPEs) offer potential alternatives to the widely-used styrenic TPEs.

scholarly journals Hydrogen bonding and thermoplastic elastomers – a nice couple with temperature-adjustable mechanical properties

Soft Matter ◽  
2018 ◽  
Vol 14 (14) ◽  
pp. 2701-2711 ◽  
Author(s):  
Elisabeth Wittenberg ◽  
Andreas Meyer ◽  
Steffen Eggers ◽  
Volker Abetz
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Bonding ◽  
Thermoplastic Elastomers ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Styrene Butadiene ◽  
Hydrogen Bonded

Hydrogen bonded supramolecular styrene–butadiene copolymers are investigated regarding their structure–property relationships using DSC, DMA, FTIR and SAXS.

The Influence of Plasticizer Nature and of Processing Mode Upon the Characteristics of Flexible Poly(vinyl chloride) Composites

2019 ◽  
Vol 56 (4) ◽  
pp. 845-851
Author(s):  
Alina Elena Coman ◽  
Augusta Raluca Gabor ◽  
Cristian Andi Nicolae ◽  
Valentin Raditoiu ◽  
Gheorghe Hubca ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vinyl Chloride ◽  
Oxygen Index ◽  
Thermal Analyses ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index ◽  
Elongation At Break ◽  
Processing Mode ◽  
Poly Vinyl Chloride ◽  
Reinforcing Agent

The topic of this paper refers to the influence of the plasticizer and the processing mode upon the characteristics of the poly(vinyl chloride) (PVC) composites. Thereby, in this study two types of industrial plasticizers were used to highlight their influence upon the properties of final composites. The employed lubricant was stearic acid, the most common and cheapest additive used in the industry for cables manufacturing. For economic reasons, calcium carbonate of 2 m size was used as reinforcing agent. Further on, two sets of samples were prepared, targeting the influence of the processing mode upon the properties of final composites. Beside the structure (by FT-infrared), thermal behavior (thermal analyses and differential scanning calorimetry) and mechanical properties (dynamic mechanical analyses, tensile strength and elongation at break) of PVC composites, the limiting oxygen index (LOI) and the overall morphology of the samples were also investigated.

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