Natural Rubber-Toughened Polystyrene: Effects of Mixing Procedure and Maleic Anhydride Content on Impact Property and Phase Morphology

2013 ◽  
Vol 747 ◽  
pp. 607-610 ◽  
Author(s):  
Saravalee Saengthaveep ◽  
Sadhan C. Jana ◽  
Rathanawan Magaraphan
Keyword(s):  
Maleic Anhydride ◽  
Natural Rubber ◽  
Impact Energy ◽  
Rubber Particle ◽  
Melt Blending ◽  
Gel Content ◽  
Rubber Toughened ◽  
One Step ◽  
The One ◽  
The Impact

The toughening of polystyrene (PS) by melt blending with natural rubber (NR) was prepared in a brabender plasticorder. Two kinds of processing had been used: (a) one-step mixing in which the three components of PS (60 wt%), NR (40 wt%) and maleic anhydride (MA) were simultaneously introduced in the mixer; (b) two-step mixing in which NR and MA were separately premixed before the final mixing with PS. The effect of MA loading (3 and 5 phr) on gel content, impact energy and morphology of PS-NR-MA blend were further investigated. The results showed that the incorporation of NR into PS increased the impact energy of the blend. The results also showed a significant effect of the different mixing procedures on the properties of PS-NR-MA blend. High contents of unreacted MA and gel were found in the blend obtained by the one-step mixing, whereas the blend prepared by the two-step mixing showed lower values in both unreacted MA and gel content. On the other hand, the impact energy of the blend prepared by one-step mixing was slightly higher than that of the blend prepared by two-step mixing. This is due to the decreased molecular weight of NR in the formerly prepared MNR of the two-step mixing. For the effect of MA loading, the decrease of unreacted MA content, gel content and rubber particle size were found at low concentration of MA.

Phase Morphology, Thermal and Mechanical Properties of Compatibilized Nylon12/Natural Rubber Blends Using PS/MNR

2013 ◽  
Vol 844 ◽  
pp. 53-56
Author(s):  
Saravalee Saengthaveep ◽  
Sadhan C. Jana ◽  
Rathanawan Magaraphan
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Moisture Absorption ◽  
Rubber Particle ◽  
Impact Resistance ◽  
Phase Morphology ◽  
Thermal And Mechanical Properties ◽  
Binary Blend ◽  
Polyamide 12 ◽  
The Impact

To produce a tough material for application demanding high impact resistance and low moisture absorption, melt blending of Nylon12 (Polyamide 12, PA12) and natural rubber (NR) was carried out in a brabender plasticorder at 210 °C with rotor speed of 70 rpm in the presence of polystyrene/maleated natural rubber (PS/MNR) blend as a compatibilizer. The effect of compatibilizer content (1, 3, 5, 7 and 10 phr) on phase morphology, thermal, and mechanical properties of [Nylon12/NR]/[PS/MNR] blends was investigated by using SEM, DSC, and Izod impact tester, respectively. The result revealed that PS/MNR blend improved the compatibility of Nylon12/NR blends efficiently due to the presence of amide linkage at the interfaces from the reaction between the reactive groups of MNR and the NH2 end groups of Nylon12 during mixing. A fine phase morphology (good dispersion and small dispersed phase size of NR domains in Nylon12 matrix) of [Nylon12/NR]/[PS/MNR] blends was observed at the optimum compatibilizer content of 7 phr, relating to the improvement of mechanical property. The impact energy of [Nylon12/NR]/[PS/MNR] blends was 503 J/m higher than that of neat Nylon12 (115 J/m) and Nylon12/NR binary blend (241 J/m) due to the toughening effect of rubber and proper morphology. The melting temperature of all blends did not change obviously from thermal analysis. However, the presence of rubber particle obstructed the crystallization of Nylon12 phase, leading to the decreasing of %crystallinity from 93% to around 70%.

scholarly journals Performance Analysis and Optimization of CRNs Based on Fixed Feedback Probability Mechanism with Two Classes of Secondary Users

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yuan Zhao ◽  
Hongyi Li ◽  
Jiemin Liu
Keyword(s):  
Performance Indicators ◽  
Three Dimensional ◽  
Secondary Users ◽  
Lower Priority ◽  
Fixed Parameter ◽  
One Step ◽  
The One ◽  
The Impact ◽  
Retransmission Control ◽  
Transfer Probability

In this paper, we conduct a research based on the classified secondary users (SUs). SUs are divided into two categories: higher-priority SU1 and lower-priority SU2, and two types of users generate two types of packets, respectively. Due to the lowest spectrum usage rights of SU2 packets, the SU2 packets’ transmission is easily interrupted by other packets with higher rights. With the purpose of controlling the SU2 packets’ retransmission behavior, we introduce two system parameters, namely, feedback threshold T and feedback probability q. When the amount of SU2 packets in the buffer reaches the feedback threshold T, the interrupted SU2 packets either enter the buffer with probability q for retransmission or leave the channel by probability 1−q, where q is a fixed parameter. We construct a three-dimensional Markov model based on the presented retransmission control mechanism and derive some important performance indicators of SU2 packets based on the one-step transfer probability matrix and steady-state distribution. Then, we analyze the impact of some key parameters on the performance indicators through numerical experiments. Finally, we establish a cost function and use particle swarm optimization algorithm to optimize the feedback threshold and feedback probability.

scholarly journals Stress Transfer Mechanism of Flange in Split Hopkinson Tension Bar

2020 ◽  
Vol 10 (21) ◽  
pp. 7601
Author(s):  
Hyunho Shin ◽  
Sanghoon Kim ◽  
Jong-Bong Kim
Keyword(s):  
Stress Transfer ◽  
Transfer Mechanism ◽  
Explicit Finite Element ◽  
Impact Theory ◽  
Quantitative Basis ◽  
Split Hopkinson ◽  
One Step ◽  
The One ◽  
The Impact ◽  
Split Hopkinson Tension Bar

To reveal the stress transfer mechanism of the flange in a split Hopkinson tension bar, explicit finite element analyses of the impact of the hollow striker on the flange were performed across a range of flange lengths. The tensile stress profiles monitored at the strain gauge position of the incident bar are interpreted on a qualitative basis using three types of stress waves: bar (B) waves, flange (F) waves, and a series of reverberation (Rn) waves. When the flange length (Lf) is long (i.e., Lf > Ls, where Ls is the striker length), the B wave and first reverberation wave (R1) are fully separated in the time axis. When the flange length is intermediate (~Db < Lf < Ls, where Db is the bar diameter), the B and F waves are partially superposed; the F wave is delayed, then followed by a series of Rn waves after the superposition period. When the flange length is short (Lf < ~Db), the B and F waves are practically fully superposed and form a pseudo-one-step pulse, indicating the necessity of a short flange length to achieve a neat tensile pulse. The magnitudes and periods of the monitored pulses are consistent with the analysis results using the one-dimensional impact theory, including a recently formulated equation for impact-induced stress when the areas of the striker and bar are different, equations for the reflection/transmission ratios of a stress wave, and an equation for pulse duration time. This observation verifies the flange length-dependent stress transfer mechanism on a quantitative basis.

scholarly journals A review on graft compatibilizer for thermoplastic elastomer blend

2021 ◽  
Vol 2080 (1) ◽  
pp. 012003
Author(s):  
K.K. Nitiyah ◽  
Luqman Musa ◽  
M.S.M. Rasidi ◽  
Shayfull Zamree Abd Rahim ◽  
Rozyanty Rahman ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Natural Rubber ◽  
Thermoplastic Elastomer ◽  
Synthetic Polymers ◽  
The Other ◽  
Poly Lactic Acid ◽  
Melt Blending ◽  
Internal Mixer ◽  
The Impact ◽  
Elastomer Blend

Abstract A biodegradable thermoplastic elastomer (TPE) blend is developed by blending poly (lactic acid) (PLA) and natural rubber (NR) or epoxidized natural rubber (ENR) and it is a sustainable substitution in recent years for synthetic polymers. PLA is high in mechanical strength and compostable, but it is highly stiff and brittle. The incorporation of NR or ENR to PLA increases the impact strength and toughness of PLA. However, the disparity in polarity between PLA and elastomer phase like NR and ENR results in TPE blend being incompatible. Hence, compatibilization is essential to improve its polarity and develop interactions. Compatibilizer that composed of two different polymer is known is graft compatibilizer with the aid of grafting agent. The graft compatibilizers are divided into two categories. The first type is made up of one polymer and grafting agent and, the other one is composed of two polymer groups and grafting agent. These two types of graft compatibilizer can be prepared via two different method such as direct melt blending and solution. Apart from this, the TPE blend is produced via the melt blending technique with mixing machines such as internal mixer and extruder. This article has reviewed the preparation of the graft compatibilizer and blending technique of TPE. Based on the findings, the graft compatibilizers has a significant role in improving miscibility and compatibility across blend composed of different phase.

Sentinel Nodal Micrometastases Detected by the One- Step Nucleic Acid Amplification Whole Node Assay and the Impact on Adjuvant Treatment and Outcomes in Early Breast Cancers: The First Report from Thailand

2021 ◽  
Vol 104 (5) ◽  
pp. 764-771
Keyword(s):  
Adjuvant Treatment ◽  
Survival Benefit ◽  
Systemic Chemotherapy ◽  
Lymph Node Biopsy ◽  
Nucleic Acid Amplification ◽  
Node Biopsy ◽  
One Step ◽  
The One ◽  
The Impact ◽  
Osna Assay

Background: The advent of sentinel lymph node biopsy (SLNB) and improvements in histopathological and molecular analysis have increased the detection rate of nodal micrometastases. As compare with conventional method, the one-step nucleic acid amplification (OSNA) assay might detect higher cases of SLN micrometastases. Objective: The present study aimed to assess the impact of OSNA assay on micrometastases detection rate and potential benefit in terms of adjuvant treatment and survival outcome in early breast cancer. Materials and Methods: A retrospective review of patients with sentinel node (SLN) micrometastasis detected by the OSNA assay between 2015 and 2019 was carried out. Clinicopathological, adjuvant treatment, and follow-up data were collected. Ten-year survival benefit with adjuvant chemotherapy was calculated using PREDICT online, version 1.2 (https://breast.predict.nhs.uk/). Results: Between November 2015 and December 2019, 78 out of 721 patients (10.8%) were positive for micrometastasis based on OSNA detection. Three-fourth of cases received adjuvant systemic chemotherapy and 57% were given taxane-based regimen. Using the PREDICT online tool, an estimated 10-year survival in patients who received adjuvant systemic chemotherapy and who did not, were 75% and 66%, respectively (p=0.018). A 10-year survival benefit from chemotherapy among patients who received systemic chemotherapy was 8% compared with 4% with no-adjuvant-therapy cohort. Conclusion: The OSNA assay allows for a more precise detection of SLN micrometastasis compared to conventional pathology and could guide therapeutic decision making. In patients with micrometastasis who received adjuvant systemic chemotherapy, the estimated overall 10-year survival was improved. Keywords: Axillary staging, Breast cancer, Micrometastases, OSNA, Sentinel lymph node biopsy

Mechanical Properties and Environmental Stress Cracking Resistance of Rubber Toughened Polyester/Clay Composite

2012 ◽  
Vol 576 ◽  
pp. 318-321 ◽  
Author(s):  
Bonnia Noor Najmi ◽  
Sahrim Haji Ahmad ◽  
Surip Siti Norasmah ◽  
S.S. Nurul ◽  
Noor Azlina Hassan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Natural Rubber ◽  
Stress Cracking ◽  
Rubber Toughened ◽  
Environmental Stress Cracking ◽  
Liquid Natural Rubber ◽  
Polyester Composite ◽  
Polyester Matrix ◽  
The Impact

Crosslinked polyester clay nanocomposites were prepared by dispersing originically modified montmorillonite in prepromoted polyester resin and subsequently crosslinked using methyl ethyl ketone peroxide catalyst at different clay concentration. Cure process and the mechanical properties of rubber toughened polyester clay composite have been studied. Rubber toughened thermoset polyester composite were prepared by adding 3 per hundred rubber (phr) of liquid natural rubber (LNR) was used in the mixing of producing this composite. Modification of polyester matrix was done due to the brittle problem of polyester composite. Addition of LNR will increase the toughness of composite and produce ductile polyester. Two types of composites were produced which is clay-lnr polyester composite and clay polyester composite. Addition of liquid natural rubber significantly increased the impact strength and flexural properties. Result shows that addition of 6% of clay-lnr composite give good properties on impact, strength and flexural. From the ESCR test, both composites showed good resistance to environmental.

Utilization of tyre rubber hybrid with ceramic and wood for impact energy absorption application

2021 ◽  
pp. 096739112110080
Author(s):  
M Sermaraj ◽  
K Ramanathan ◽  
A Athijayamani
Keyword(s):  
Composite Materials ◽  
Impact Strength ◽  
Impact Energy ◽  
Rubber Particle ◽  
Resin Matrix ◽  
Wood Dust ◽  
Neat Resin ◽  
Resin Sample ◽  
Morphological Studies ◽  
The Impact

The used tyre rubber, scrap ceramic tiles and wood dust are largely dumped into landfills, which create environmental pollution to the surrounding. The recycling of tyre rubber is very limited, but it has good property to absorb the impact energy. Hence, these materials are used to prepare the composite in the present work. Composite materials were prepared by the resin transfer moulding method with different weight percentage of particles. The tensile, flexural and impact strength of composite specimens were compared with other combination of composites and also with the neat resin sample specimen. The tensile and flexural strength of composites were decreased with the addition of the rubber. But, the rubber particle with the ceramic in the resin matrix increases the impact strength of composite by 45.91% when compared with the neat resin sample. The addition of rubber enhances the impact strength of composite materials with all the combination of particles. The better distribution and good interfacial adhesion of particles with a resin matrix along the fractured surface were observed by the scanning electron microscope. And also, the nature of failure was identified by morphological studies.

Analysis of Non-Classical Models which Have been Subjected to Percussive Loads Using Equations of Energy and Power

2014 ◽  
Vol 1036 ◽  
pp. 608-613 ◽  
Author(s):  
Krzysztof Jamroziak ◽  
Miroslaw Bocian
Keyword(s):  
Energy Dissipation ◽  
Impact Energy ◽  
Dynamic Models ◽  
Specific Impulse ◽  
Pulse Excitation ◽  
Classical Dynamic ◽  
Simple Description ◽  
Classical Models ◽  
The One ◽  
The Impact

The article presents an analysis of impact energy dissipation process with selected non-classical dynamic models. Identification of impact energy dissipation phenomena in layered mechanical systems (for example: composite ballistic shields) is a great challenge, because on the one hand a model with parameters responsible for the energy dissipation is being sought on the one hand and on the other it is necessary to optimise the number of parameters. The sought model should be reduced to a simple description of the phenomenon and should contain a complex reproduction of the whole mechanical system. In this case the impact energy dissipation was described using selected degenerate systems. Models were treated by extortion surge having a specific impulse of force. The mathematical description of the pulse excitation was carried out using the energy and potency balance equations. The verification of mathematical identification equations was conducted using a computer simulation technique for the selected model’s parameters.

scholarly journals Prominent Crystallization Promotion Effect of Montmorillonite on PTT/PC Blends with PTT as the Continuous Phase

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 541
Author(s):  
Meiling Xue ◽  
Yingjie Liu ◽  
Kanghui Lv ◽  
Shaowu Han ◽  
Shengqiang Gao ◽  
...  
Keyword(s):  
Shear Force ◽  
Phase Interface ◽  
Continuous Phase ◽  
Melt Blending ◽  
Step Method ◽  
Promoting Effect ◽  
Crystallization Peak ◽  
One Step ◽  
The One ◽  
Crystallization Promoter

To regulate the crystallization of poly(trimethylene terephthalate) (PTT) retarded by melt blending with polycarbonate (PC), the crystallization of the PTT/PC blend was investigated employing nano-montmorillonite (MMT) as a crystallization promoter with PTT as the continuous phase. The results showed that MMT exhibits a significant promoting effect on PTT crystallization; the presence of 1 wt. % MMT shifts the initial and peak crystallization temperatures of the 70/30 PTT/PC blend to ~17 °C and ~32 °C, respectively. Additionally, the full width at half maximum (FWHM) narrows by ~45%, and the ΔHc increases by 3.7 J.g−1. The accelerating effect of MMT is determined by its distribution and dispersion which depends on the shear intensity, mixing mode, and loading. MMT is easier to exfoliate via the two-step method than by the one-step method. The distribution in the PTT phase is enriched along the phase interface forming an MMT layer. This endows sections of the PTT with abundant nuclei and thus crystallization is promoted markedly compared with the one-step method. Moreover, the finer MMT migrates more readily to the interface to cause a much smoother phase interface. However, a secondary crystallization peak appears when the shear force is not sufficient enough to make MMT finely dispersed, in case of the two-step method and the MMT content is increased to 3 wt. %. The mixing temperature shows little effect on the acceleration of MMT on the crystallization of PTT/PC compared with the shear force. Only when MMT did not exfoliate or uncomplete did the presence of epoxy resin help to promote crystallization because of the improved MMT dispersion.

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