Nitrile Butadiene Rubber Particles Research Articles

Design of heat‐triggered shape memory polymers based on ethylene‐acrylic acid copolymer/nitrile‐butadiene rubber thermoplastic vulcanizates

AbstractHeat‐triggered shape memory polymers (HSMPs) consisting of ethylene‐acrylic acid copolymer (EAA) and nitrile‐butadiene rubber (NBR) were fabricated by peroxide‐induced dynamic vulcanization; meanwhile, in order to realize rapid and reconfigurable shape fixity and shape recovery, a facile and effective strategy was designed. Morphological structure and interface interaction are decisive factors for HSMPs, the FE‐SEM images showed the average diameter of NBR particles in EAA/NBR TPVs was 5 to 8 μm and the strong interface interaction between EAA matrix and NBR particles provided critical assistance in keeping the temporary shape of deformed rubber particles and storing stronger elastic driving force. The shape memory behavior of EAA/NBR TPVs was characterized and the result demonstrated that excellent shape‐fixity (>91%), shape‐recovery (>93%), and fast recovery speed (<30 s) could be obtained at suitable deformation temperature of 95°C. The results of dynamic mechanical analysis and shape memory research showed that the high modulus value supported the improvement of shape‐fixity ratio and the appropriate ratios of EAA/NBR TPVs were the key factors for excellent shape memory performance. The novel HSMPs expected to open up potential applications in the field of sensors and self‐assembling smart devices.

Mullins Effect and Its Reversibility for Thermoplastic Vulcanizates Based on Ethylene–Acrylic Acid Copolymer/Nitrile–Butadiene Rubber Blends

Mullins effect during uniaxial cyclic compression tests, together with its reversibility, of ethylene–acrylic acid copolymer (EAA)/nitrile–butadiene rubber (NBR) thermoplastic vulcanizates (TPVs) were investigated systematically. The results showed that EAA/NBR TPVs had excellent mechanical properties when the weight ratio was 40/60. Morphology studies showed that sphere-like NBR particles were dispersed evenly in the etched TPVs surface with diameters of 5–8 μm. The experimental results of Mullins effect indicated that a stress softening phenomenon in the stress–strain curves of EAA/NBR TPVs during the uniaxial loading–unloading cycles could be observed obviously; moreover, the reversibility of Mullins effect could be significantly enhanced by increasing heat treatment temperature.

Dynamically vulcanized high-density polyethylene/nitrile butadiene rubber blends compatibilized by chlorinated polyethylene

Thermoplastic vulcanizates (TPVs) based on high-density polyethylene (HDPE)/nitrile butadiene rubber (NBR) blends were prepared by dynamic vulcanization where chlorinated polyethylene (CPE) was used as a compatibilizer. The effects of CPE on mechanical properties, Mullins effect, dynamic mechanical properties, and morphology of the blends were investigated systematically. Experimental results indicated that CPE had an excellent compatibilization on the HDPE/NBR blends. Dynamic mechanical analysis studies showed that the glass transition temperature of NBR phase was slightly shifted toward higher temperature with the CPE incorporation, leading to the increasing interface compatibility. Mullins effect results showed that the compatibilized HDPE/NBR blend had relatively lower residual deformation and internal friction than that of HDPE/NBR blend, indicating the improvement of elasticity. Morphology studies showed that the size of the NBR particles was decreased with the existence of CPE; moreover, the fracture surface of HDPE/CPE/NBR TPV was relatively smoother than that of HDPE/NBR blend.

Impact strength, fracture toughness and hardness improvement of PMMA denture base through addition of nitrile rubber/ceramic fillers

Abstract Background/purpose PMMA resin mostly used the fabrication of denture base by heat-curing technique. It has poor strength, including low impact strength and low fatigue resistance. In this work the combination of nitrile butadiene rubber (NBR) with two types of ceramic fillers (Al2O3 and YSZ, respectively) on the mechanical properties of denture base are investigated. Materials and methods The denture base composites were fabricated by incorporating PMMA powder, 0.5 wt% of benzoyl peroxide (BPO), fixed at 7.5 wt% NBR particles and ceramic fillers (fixed at 5 wt%) as powder components. In total, 180 specimens were prepared for all tests and divided into 6 groups for each test (N = 10) coded G1–G6. Group 1 as the control group (without fillers) was mixed between PMMA powder and BPO; whereas the other five groups (G2–G6) were reinforced with NBR particles and different concentrations of ceramic fillers. The morphology of the fracture surface of specimens was examined by Field Emission Scanning Electron Microscopy (FESEM). Results Statistical analysis, shows that the mean impact strength (IS) and fracture toughness (KIC) of control dentures when compared to reinforced PMMA at 7.5% NBR and 2.5% Al2O3/2.5% YSZ improved significantly (5.27 ± 0.21–10.25 ± 0.41 kJ/m2 and 1.60 ± 0.24–2.58 ± 0.30 MPa·m1/2, respectively). Conclusion The reinforced PMMA denture bases are significantly different in IS and KIC between study groups (P = 0.001). However, the Vickers hardness (VH) is statistically not significantly different (P > 0.05).

Modification of Rubber Particles and Ceramic Fillers on PMMA Denture Base Materials

The purpose of this study is to investigate the effect of nitrile butadiene rubber (NBR) particles and ceramic fillers on the density of PMMA denture base materials. The denture base was prepared based on the mixture of PMMA powder and MMA liquid. The density of the denture base has been modified by adding three different ratios of nitrile rubber (5, 7.5 and 10 wt %), three types of ceramic fillers (Al2O3, YSZ and SiO2, respectively) fixed at 5 wt %, 0.5% of benzoyl peroxide (PBO) and ethylene glycol dimethacryate (10 wt% EGDMA). The powder/liquid (P/L) was mixed by 2.5:1 g ratio. At 10 wt% of NBR the denture base density has reduced to 50%. Furthermore, the addition of ceramic fillers together with NBR particles has also reduced the denture base density. The density data was statistically analysed by on-way (ANOVA) and the values were significantly effect when addition of rubber particles in PMMA denture base composite (p < 0.05).Therefore, the density issue can be easily adjusted in retention and stability of denture base in the patient mouth.

Pmma Denture Base Composites Reinforced by Nitrile Rubber and Ceramic Fillers

Poly(methyl methacrylate) (PMMA) denture base composites were fabricated by incorporating nitrile butadiene rubber (NBR) particles and ceramic fillers (Al2O3, YSZ, and SiO2). PMMA powder was mixed with liquid methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) as crosslinking agents. The different types of ceramic fillers were fixed at 5 wt.% and NBR particles in proportions of 5, 7.5 and 10 wt.%, respectively, mixed with PMMA. The impact strength (IS) increased and the fracture toughness (KIC) decreased with the increase of NBR content in PMMA matrix. The composites with Al2O3 showed better IS and KIC when compared to YSZ and SiO2 particles. It has been demonstrated that the combination of 10 wt.% NBR/5 wt.% Al2O3 produced the optimum density (1.049 g/cm3), IS (7.41 KJ/m2), KIC (2.45 MPa.m1/2) and statistically the values was significantly increased (p < 0.05).

Influence of Al2O3/ Y-TSZ Mixture as Filler Loading on the Radiopacity of PMMA Denture Base Composites

The radiopacity of alumina/yttrium stabilizer zirconia (Al2O3/Y-TSZ) particles with nitrile butadiene rubber (NBR) dispersed in PMMA denture base material has been investigated. PMMA matrix without filler was prepared from PMMA powder with 0.5% benzoyl peroxide (PBO) as the control material. The similar PMMA matrix was mixed with Al2O3/Y-TSZ (1:1) together with NBR particles as the reinforcement. The amount of NBR was fixed at 7.5wt %, however, Al2O3/Y-TSZ varied from 1 to 10wt %, respectively. Samples with 4mm thickness for each composition were irradiated using 60 KV, 10mA, 0.4 s to examine their radiopacity. This radiopacity was compared to radiopacity of aluminum plate which having the same thickness. The result shows that the radiopacity (i.e. the lower optical density the higher radiopacity) of reinforced PMMA matrix slightly increased from 1.40 to 1.05, respectively, with the increased of filler loading compared to unreinforced PMMA matrix.

Poly(methyl methacrylate) denture base composites enhancement by various combinations of nitrile butadiene rubber/treated ceramic fillers

Nitrile butadiene rubber (NBR) particles as impact modifier mixed with treated ceramic fillers (aluminum oxide, yttria-stabilized zirconia, and silicon dioxide) were used to reinforce poly(methyl methacrylate) (PMMA) denture base material. The powder components are PMMA, benzoyl peroxide, NBR (5, 7.5, and 10 wt%), and ceramic fillers (5 wt%) treated with silane. The liquid components are 90% methyl methacrylate and 10% ethylene glycol dimethacryate. Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy analyses confirmed that the ceramic fillers were successful. The morphology of fracture surfaces of specimens was characterized using field emission scanning electron microscopy. The impact strength (IS) and fracture toughness ( KIC) improved significantly. IS increased to 56% (8.26 kJ m−2) and 73% (2.77 MPa m1/2) for KIC when compared with unreinforced PMMA matrix. Statistical analyses of data results were significantly improved ( p < 0.005). PMMA denture base reinforced by NBR particles mixed with treated ceramic fillers are ideally suited for dentistry applications with the ability to withstand high mastication forces.

Effects of NBR Particle Size on Performance of Carbon Fiber–Reinforced Paper-Based Friction Material

In the present work, three different sized nitrile–butadiene rubber (NBR) particles were used to modify carbon fiber–reinforced paper-based friction material (CFRPF). The effects of NBR particle size on performance of CFRPF were studied. The microstructure and properties of the samples were investigated by scanning electron microscopy, thermal analysis, and wet friction performance testing. Experimental results indicated that there were four stages in the thermal degradation of NBR-modified CFRPF. NBR particle size had a great effect on the first degradation stage (100–300°C). The highest friction coefficient was obtained with the sample containing the finest NBR particles. The wear rate of the friction materials decreased with an increase in NBR particle size. However, NBR particle size had little influence on the wear rate of the couple plate. The sample containing coarse NBR particles showed excellent friction stability under oil-lubricated conditions.

Mechanical Properties of PMMA Denture Base Reinforced by Nitrile Rubber Particles with Al2O3/YSZ Fillers

The aim of this research study is to investigate the effect of filler loading of alumina/yttrium stabilizer zirconia (Al2O3/YSZ) filler with nitrile-butadiene rubber (NBR) particles filled PMMA denture base material on the mechanical properties. The PMMA matrix (control group) was prepared 0.5% benzoyl peroxide (BPO) with PMMA powder as initiator. Al2O3/YSZ ceramic powders by ratio 50/50 using 1,3,5,7 and 10 wt% as filler loading and then, mixed with10 wt% NBR particles, respectively, into PMMA matrix using the internal mixture as powder mixture (powder component). The liquid component consists of 90% of methyl methacrylate (MMA) and 10% ethylene glycol dimethacryate (EGDMA as the crosslinking agent). The mechanical properties of NBR/treated ceramic fillers in PMMA composites were tested using impact strength (IS) and fracture toughness (KIC). The morphology of fracture surface of specimens was characterized using field emission scanning electron microscopy (FESEM). The IS and KIC values increased to 10.25 KJ/m2 and 2.58MPa.m1/2 by 5% of loading filler compared to control group 5.27 KJ/m2 and 1.6MPa.m1/2, respectively. Statistically, shows that the IS and KIC for PMMA reinforced by NBR and Al2O3/YSZ is significantly improved (P < 0.05). Therefore, this reinforced PMMA denture base is suitable to be used as prosthodontics applications.

Dynamically Vulcanized Nitrile Butadiene Rubber/Acrylonitrile-Butadiene-Styrene Terpolymer Blends Compatibilized by Styrene-Butadiene-Styrene Block Copolymer

Thermoplastic vulcanizates (TPVs) based on nitrile butadiene rubber (NBR)/ acrylonitrile-butadiene-styrene (ABS) blends were prepared by dynamic vulcanization, and then compatibilized by styrene-butadiene-styrene block copolymer (SBS). The effects of SBS compatibilizer on mechanical properties, Mullins effect, and morphological properties of the TPVs were investigated systematically. Experimental results indicated that SBS had an excellent compatibilization effect on the dynamically vulcanized NBR/ABS TPVs. The tensile strength increased from 9.4 to 15.8 MPa and the elongation at break went through a maximum value when the dosage of SBS was only 1 phr. Mullins effect results showed that the compatibilized NBR/ABS TPV had relatively lower residual deformation and internal friction loss than the NBR/ABS TPV, indicating the improvement of elasticity. Morphology studies showed that the vulcanized NBR particles were dispersed evenly in the TPVs and the dimensions of NBR particles were decreased remarkably with the incorporation of SBS compatibilizer.

Highly toughened poly(vinylidene fluoride)/nitrile butadiene rubber blends prepared via peroxide-induced dynamic vulcanization

Nitrile butadiene rubber (NBR) toughened poly(vinylidene fluoride) (PVDF) blends were prepared via dynamic vulcanization in the presence of dicumyl peroxide (DCP). A super toughened PVDF/NBR blend was achieved with 28 wt% NBR, showing Izod impact strength of 77.5 kJ/m2, which was 6–7 times higher than the pure PVDF. The effects of the NBR incorporation on morphology and properties of the blends were investigated. Good interfacial interaction was found between the PVDF continuous phase and crosslinked spherical NBR particles with diameter of 1–3 μm. The complex viscosity and storage modulus of the blends increased significantly with increasing NBR content. The incorporation of the NBR component decreased the thermal stability of the PVDF/NBR blends, while the mass of residual char of the blends was much higher than that of pure PVDF and NBR.

Dynamically Vulcanized Nitrile Butadiene Rubber/Ethylene-vinyl Acetate Copolymer Blends Compatibilized by Chlorinated Polyethylene

Thermoplastic vulcanizates (TPVs) based on nitrile butadiene rubber (NBR)/ethylene-vinyl acetate copolymer (EVA) blends were prepared by dynamic vulcanization, with the TPVs being compatibilized by chlorinated polyethylene (CPE). The effects of CPE compatibilizer on the mechanical and morphological properties of the TPVs were investigated systematically. Experimental results showed that the dynamically vulcanized NBR/EVA blends compatibilized by CPE had obvious elastomeric behavior and improved mechanical properties, indicating that CPE had a good compatibilization effect on the NBR/EVA TPVs. The fracture surface morphology of the compatibilized NBR/EVA TPV was somewhat rougher than that of uncompatibilized NBR/EVA; the large deformation during the tensile fracture could recover well and less notable, smaller diameter drawn fibrils were observed. Moreover, the interface interaction was strong and there was no obvious microphase separation. NBR particles were dispersed evenly in the etched surfaces of the NBR/EVA/CPE TPV.