Polymer Alloys Research Articles

Double percolation and segregated structures formed in polymer alloy with excellent electrical conductivity

AbstractIt can efficiently enhance electrical conductivity and electromagnetic interference (EMI) shielding performance to construct segregated structures in conductive polymer composites (CPCs). However, it can also deteriorate mechanical properties due to weak interfacial interaction between matrixes and fillers. So segregated structures CPCs that polycarbonate/acrylonitrile‐butadiene‐styrene (PC/ABS) was coated by ABS/multi‐walled carbon nanotubes (ABS/MWCNTs) were prepared by solution‐mechanical mixing method. The surface resistivity of the segregated composites achieved 105 Ω/sq with only 0.05 wt% of MWCNTs and was lower than composites prepared by melt and solution mixing methods. Tensile strength of the segregated composites was nearly 40 MPa. The EMI shielding values of the segregated composites with 7 wt% of MWCNTs were 50 to 80 dB as high as the uniform structure composites with 10 wt% of MWCNTs between 30 MHz and 1 GHz electromagnetic frequency. All the results displayed that this work provided a novel and efficient method to produce segregated conductive composites for antistatic and EMI shielding applications.

Mechanical and Corrosion Assessment of Friction Self-Piercing Rivet Joint of Carbon Fiber-Reinforced Polymer and Magnesium Alloy AZ31B

Abstract In the present work, thermoset carbon fiber–reinforced polymer (CFRP) was spot joined to magnesium alloy AZ31B by a friction self-piercing riveting (F-SPR) process. Lap shear tensile and cross-tension testing were used to evaluate the mechanical joint performance. An average lap shear tensile load of 5.18 kN was achieved, while an average of 2.81 kN was found from cross-tension testing. All F-SPR samples showed a pullout of AZ31B after mechanical testing, indicating good mechanical interlocking between the steel rivet and AZ31B. Corrosion potential was measured for each material to establish the galvanic corrosion characteristics. As expected, AZ31B was found to be the most active, while thermoset CFRP was the most noble. The steel rivet fell between the AZ31B (active) and the thermoset CFRP (noble). Salt fog corrosion testing (ASTM B-117) was performed to evaluate the corrosion performance of the uncoated F-SPR joint. With up to 200 h of exposure, the post-corroded F-SPR joint integrity retained 81.2% of the pre-exposure F-SPR joint strength with AZ31B pullout failure mode. From cross-sectional analysis of the F-SPR joint, extensive corrosion of AZ31B was observed at the joint and other exposure areas. However, steel rivet was not significantly corroded due to sacrificial anode effect by which AZ31B corroded first in the galvanic couple.

Trifunctional quinoxaline‐based maleimide and its polymer alloys with benzoxazine: Synthesis, characterization, and properties

AbstractNovel quinoxaline‐based trismaleimide (2,3‐di[3‐maleimido]phenyl‐6‐ maleimidoquinoxaline, namely TQMI) and its polymer alloys with 3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazine (P‐a) were successfully prepared and characterized. Differential scanning calorimetry investigation of TQMI exhibited distinct double exothermic peaks, which implied that the curing behavior of different type of maleimide group was discrepant. The curing temperature of P‐a/TQMI prepolymers was lower than that of both neat TQMI and P‐a monomer. The temperatures at 5% (T5) and 10% (T10) weight loss and the char yield (Yc) of cured TQMI at 800°C reached 513°C, 524°C, and 63.5%, respectively, which were much higher than the record of traditional 4,4′‐bismaleimideodiphenylmethane (BMDPM) resin as well as most of other reported bismaleimide resins. Moreover, the addition of TQMI enhanced thermal stability, glass transition temperature (Tg), and limiting oxygen index of benzoxazine resin dramatically. Attractively, the Tg value of P‐a/TQMI copolymer at 30 wt% TQMI loadings was approximately 20°C higher than that of P‐a/BMDPM copolymer owing to the bulky quinoxaline group.

Facile preparation and application performance evaluation of SBS/C9 petroleum resin blends as modifier for high viscosity asphalt

To reduce the cost of high viscosity asphalt, SBS/C9 petroleum resin blends (SPR) were prepared via a simple one-pot polymer alloying process as modifiers for high viscosity asphalt in this study. The chemical characteristics of SRP and its modification effect on asphalt were studied and also compared with the traditional modifier (Tafpack-Super, abbreviated as TPS). Results show that SPR modifier contains more oxygen-containing functional groups than the TPS modifier. The molecular weight of SPR modifier is slightly higher but distributes over a wider range than that of the TPS modifier. Besides, its melting and crystallization temperatures of SPR modifier are lower than those of TPS modifier, thus SPR modifier has better compatibility with asphalt during production, making SPR easier to be dispersed in asphalt with smaller average particle size. Due to these reasons, SPR modifier has better modification effect on asphalt than traditional TPS modifier. Besides, the price of self-made SPR can be reduced to 29% of that of commercial TPS modifier, and the raw materials price of high viscosity asphalt with SPR modifier can reduce to 48.8% of that with TPS modifier. Therefore, SPR is a good modifier for the preparation of high viscosity asphalt with high performance and low cost.

P1073NF-U OF A NEW POLYMETHYLMETHACRYLATE MEMBRANE IMPROVES THE NUTRITIONAL STATUS AND PATIENT-REPORTED SYMPTOMS OF ELDER DIALYSIS PATIENTS

Abstract Background and Aims Malnutrition is the most powerful prognostic factor in dialysis patients, and elder dialysis patients have a higher risk of malnutrition because of multiple comorbidities and daily inactivity. Hence, it is very important to set up a dialysis prescription for preventing progression of malnutrition. We reported nutritional advantage of polymethylmethacrylate (PMMA) membrane for preventing dialysis patients from the progression of malnutrition in the previous report. NF-U has been developed with better hemocompatibility and lesser albumin leakage during the dialysis session than conventional PMMA membranes. We studied additional advantages of NF-U on the nutritional status, patient-reported symptoms and other clinical parameters in elder dialysis patients. Method This study was a retrospective one. 10 elder chronic dialysis patients of greater than 75 years old were enrolled into the study; 5 males and 5 females, the mean age was 82.8 years old, and the average dialysis vintage was 11.2 years. NF-U were installed because of low albuminemia, dry weight (DW) loss and other signs of malnutrition. The previous membrane materials were polyether polymer alloy (6), vitamin E coated polysulfone (1), on-line HDF with polyethersulfone (2) and polysulfone (1). On-line HDF were performed in predilution with the substitution volume of 12L/hr. During the observation period the dialysis prescription except dialysis membrane was not changed. Serum albumin, β2MG, CRP, nPCR, GNRI, ％CGR, DW, CTR were compared one month and four month after the replacement with NF-U. In consideration of the seasonal variation of nutritional status, DW and CTR were compared with that of one year before the study. The changes in body composition were analyzed by Inbody770® (Inbody Japan, Tokyo, Japan)at three months before and after the replacement with NF-U. We also evaluated patient-reported subjective symptoms by our original tool as “Patient-oriented Dialysis (POD)” system three months before and after NF-U installation. Results Serum albumin increased from 3.0g/dl to 3.3g/dl. GNRI increased from 87.7 to 91.4. %CGR increased from 91.9% to 102.8%. No significant changes were observed in β2MG, CRP and nPCR. Although DW had continuously decreased from 52.7kg to 51.7kg before NF-U installation, DW increased from 52.0kg to 52.7kg by NF-U. CTR did not change. Muscle volume and body fat mass also increased. Regarding subjective symptoms, total POD score was significantly improved and especially dialysis related fatigue was remarkably reduced by NF-U. Conclusion The current study clearly showed that NF-U of a new PMMA membrane improved the nutritional status of elder dialysis patients with higher risk of malnutrition although the study was a limited retrospective one. Furthermore, NF-U also improved patient-reported subjective symptoms such as fatigue which was reported as a mortality risk factor and the most important patient’s outcome. We have not yet established a golden standard or parameter to set up dialysis prescriptions properly to elder dialysis patients. However, improvement of nutritional status and fatigue are one of the most important parameters to expect better outcome of them. We conclude that NF-U should be one of the best choices to treat elder dialysis patients.

Modification of Рolymer Wastes and Obtaining Com Comрosites Based on Them Annotation

The sources of scientific literature on the research have been investigated, various approaches to the processing and modification of polymers have been analyzed and the main direction of the study have been identified. The changes in the properties of thin layers of industrially produced low-density polyethylene (LDPE) grades 10803-20 and 16603-011 operating under different climatic conditions have been studied. It has been determined that changes with different intensities occur in the structure and in this connection in the physical and mechanical properties of LDPE that was in operation at different time intervals and in different climatic conditions of the Absheron Peninsula and the Aran region: melt flow index of polymer alloy, tensile strength at break, relative extension and values of other indicators are deteriorating. In polymer samples is formed 24,2 – 28,6% of insoluble phase and as a result of oxidation up to  12,3 – 16,8% carbonyl, hydroxyl and other functional groups.

Morphology evolution of poly(lactic acid) during in situ reaction with poly(butylenesuccinate) and ethylene‐methyl acrylate‐glycidyl methacrylate: The formation of a novel 3D star‐like structure

AbstractMorphology control of polymer alloys is an attractive topic for investigators due to its ability to improve the performance of products for years. However, it is hard to control the morphology of immiscible polymer blends during melt processing. Herein, we studied the morphology evolution of poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) with the inclusion of ethylene‐methyl acrylate‐glycidyl methacrylate (EGMA). Scanning electron microscopy of both cryo‐fractured and etched cryo‐fractured samples indicates that the in situ reaction among PLA, PBS, and EGMA can induce the morphology change and result in a novel 3D star‐like structure. Rheology behaviors of the samples under different angular frequencies were used to validate the formation of 3D networks in the samples. Tensile stiffness reinforcements at both room temperature and high temperature were provided through dynamic mechanical analysis. In addition, a 10‐fold improvement in impact strength is also monitored by the unnotched impact test to indicate the superior toughening effect. Furthermore, the crystalline behavior and thermal properties of the blends were also studied. It is believed that our work not only gives a deeper understanding of the reaction‐induced morphology evolution of the PLA/PBS/EGMA blends but also reveals an avenue toward morphology control by melt processing.

CFRTP -Al alloy laser assisted joining with a high speed rotational welding technology

To reduce the defects in laser welding of carbon fiber reinforced polymer (CFRTP) and aluminum (Al) alloy and improve the mechanical properties of the joint, a high speed rotational laser welding (HSRLW) technology was introduced. The mathematical model of CFRTP-Al alloy laser joining was established and the temperature was simulated. The weld depth of aluminum alloy and the penetration depth of CFRTP/aluminum alloy joint were calculated and compared with the experimental result. It was found that the pore defects can be significantly reduced, and a high strength joint could be obtained. The simulation results agree well with the experimental results, and the strength of the CFRTP/aluminum alloy joint can be predicted by using the numerical simulation method.

Progress of Benzoxazine-based Heat Resistant Polymer Alloy

Progress of Benzoxazine-based Heat Resistant Polymer Alloy

Detection of Tool Wear in Drilling CFRP/TC4 Stacks by Acoustic Emission

Composite stacked material is widely used in many fields, such as aircraft, rocket, missile, and soon. In the process of drilling carbon fiber-reinforced polymer and titanium alloy lamination materials (CFRP/TC4, which is a typical structure in aircraft), tool wear is quick and serious, because the machining condition of the respective layers in stack is different. To ensure the drilling quality, drilling tool needs to be changed frequently. Therefore, if there is a detecting system in automatic drilling device to monitor and predict the tool wear effectively, it will help to improve the production efficiency and reduce the tool cost. Based on the experiments of drilling CFRP/TC4 stacks, the acoustic emission (AE) signals were carefully analyzed using the method of statistical analysis, spectrum analysis, and wavelet packet. The results show that the root-mean-square value of the AE signals and the energy of the wavelet packet are correlated with the tool wear. Meanwhile, experiments indicate that chips and tool fracture will cause instantaneous signal mutation, which may be appeared as disturbances. This has increased the difficulty of identifying the tool wear. With repeated experiments and comparison, it was found that the percentage of wavelet packet energy of some certain frequency sections increased with the tool wear, while some decreased. These variations will be possible to be used as features for further prediction in monitoring system.

Effect of infill materials on vibration isolation efficacy of geocell-reinforced soil beds

This paper investigates the isolation efficacy of geocell-reinforced foundation beds infilled with different materials through a series of block resonance tests. The geocell made with a novel polymeric alloy (NPA) was used in the experimental investigation. In total, five different cases — namely, unreinforced, geocell-reinforced silty sand, geocell-reinforced sand, geocell-reinforced slag, and geocell-reinforced aggregate — were considered. Presence of the geocell has resulted in improvement of screening efficacy of the foundation bed regardless of the infill material. The displacement amplitude of the geocell-reinforced bed cases was reduced by 68%, 64%, 61%, and 59%, respectively, for aggregate, slag, sand, and silty sand infill cases as compared to the unreinforced condition. Maximum isolation efficiency was observed in the presence of aggregate, among the four different infill materials. In the presence of aggregate infill, the shear modulus of the foundation bed was improved by 150%. Similarly, the peak particle velocity and peak acceleration were reduced by 57% and 48%, respectively. Further, the efficacy of mass spring dashpot (MSD) analogy was studied in predicting the frequency–displacement response of different reinforced cases. From the analytical study, a significant improvement in damping ratio of the foundation bed was observed in the presence of geocell reinforcement.

Synthesis of a benzoxazine monomer contained hyperbranched polysiloxane and the characteristics of its polymer alloys blend with bismaleimides

A novel benzoxazine monomer contained hyperbranched polysiloxane structure (HBPSi-BOZ) was synthesized via a solvent process based on the polyformaldehyde, aniline, and a new hyperbranched polysiloxane with terminal amino groups (HBPSi-NH2). The HBPSi-BOZ was then used as modified phase to blend with bismaleimides (BMIs) resin, and a polymer alloy HBPSi-BOZ/BMI was successfully prepared. The thermal resistant properties, mechanical properties, and tribological properties of HBPSi-BOZ/BMI resins with different contents of HBPSi-BOZ prepared were researched to get an optimal ratio. The thermogravimetric analysis was also carried out to study the polymerization process and stability of HBPSi-BOZ/BMI resins. The results showed that as the thermal resistance increased, the wear resistance and mechanical properties of HBPSi-BOZ/BMI resins were also enhanced.

Hybrid laser technique for joining of polymer and titanium alloy

Weight reduction of parts is of great importance in automotive and aerospace industries. Laser direct joining of dissimilar materials had been investigated previously to obtain lightweight characteristics and keep the local excellent plasticity and mechanical property. In the present work, the authors adopt the hybrid laser joining method to bond Ti6Al4V and polyamide (PA66). Laser texturing pretreatment is performed on the Ti6Al4V surface prior to the laser joining process. Oblique microgrooves with the depth ranging from 100 to 550 μm are designed and fabricated on Ti6Al4V surfaces to improve the bonding strength between Ti6Al4V and polyamide. Single lap shear tests are carried out after the laser joining process. The highest breaking force of laser joined Ti6Al4V-PA66 joints reaches around 942 N, which is high up to more than 90% of base PA66 breaking force (1043 N) and about 4.9 times of the joints with a smooth Ti6Al4V surface (194 N). The great enhancement of breaking force of the joints is attributed to the strong mechanical bonding quality between PA66 and surface-textured Ti6Al4V. The employed hybrid laser joining method shows great potential in manufacturing industries.

Effects of types of isocyanate and polyol on thermal and mechanical properties of benzoxazine-urethane polymer alloys

Polymer alloys of benzoxazine resin (BA-a) and urethane prepolymer (PU) were prepared at various BA-a : PU mass ratios (100 : 0, 80 : 20, 70 : 30 and 60 : 40) via sequential cure method. Isocyanate end capped urethane prepolymer was synthesized with isocyanates and polyols. Various types of isocyanate groups were used [i.e., TDI, MDI, IPDI and HDI] in this study. Polypropylene glycol and Poly(ethylene, diethylene adipate) glycol represent polyether polyol (E) and polyester polyol (S), respectively. Experimental results revealed that glass transition temperature (Tg), flexural strength and flexural modulus increase with decreasing PU content. Furthermore, the flexural strength and flexural modulus synergism were found in the BA-a:PU based polyester polyol at all mass ratio.

Three-dimensional Analysis of Non-stained Polymer Alloy Using Differential Phase Contrast-STEM Tomography

Three-dimensional Analysis of Non-stained Polymer Alloy Using Differential Phase Contrast-STEM Tomography

Investigation of the Joining Technology of FRP/AZ31B Magnesium Alloy by Welding and Riveting Hybrid Bonding Method.

A novel joining technology was applied to join Fiber Reinforced Polymer (FRP) and AZ31B Mg alloy, which combined the laser-arc welding source and riveting joining methods. The design idea of the stepped rivet was proposed. The weld morphology, mechanical properties, microstructures of welds under two different rivet structures were investigated. FRP and AZ31B Mg could be joined successfully by the new hybrid joining method when it used two different structural rivets. The maximum tensile shear load of the joint under stepped rivet of small size was only 800 N, while that of the joint under stepped rivet of the larger size could reach 1419 N, nearly 90% of that of FRP. There was no reaction between the FRP plate and AZ31B rivet. While the magnesium elements and aluminum elements diffused and reacted with other elements in the FRP plate/AZ31B plate interface.

Facile Generation of Polymer-Alloy Hybrid Layers for Dendrite-Free Lithium-Metal Anodes with Improved Moisture Stability.

Lithium-metal anodes are recognized as the most promising next-generation anodes for high-energy-storage batteries. However, lithium dendrites lead to irreversible capacity decay in lithium-metal batteries (LMBs). Besides, the strict assembly-environment conditions of LMBs are regarded as a challenge for practical applications. In this study, a workable lithium-metal anode with an artificial hybrid layer composed of a polymer and an alloy was designed and prepared by a simple chemical-modification strategy. Treated lithium anodes remained dendrite-free for over 1000 h in a Li-Li symmetric cell and exhibited outstanding cycle performance in high-areal-loading Li-S and Li-LiFePO4 full cells. Moreover, the treated lithium showed improved moisture stability that benefits from the hydrophobicity of the polymer, thus retaining good electrochemical performance after exposure to humid air.

Facile Generation of Polymer–Alloy Hybrid Layers for Dendrite‐Free Lithium‐Metal Anodes with Improved Moisture Stability

AbstractLithium‐metal anodes are recognized as the most promising next‐generation anodes for high‐energy‐storage batteries. However, lithium dendrites lead to irreversible capacity decay in lithium‐metal batteries (LMBs). Besides, the strict assembly‐environment conditions of LMBs are regarded as a challenge for practical applications. In this study, a workable lithium‐metal anode with an artificial hybrid layer composed of a polymer and an alloy was designed and prepared by a simple chemical‐modification strategy. Treated lithium anodes remained dendrite‐free for over 1000 h in a Li–Li symmetric cell and exhibited outstanding cycle performance in high‐areal‐loading Li–S and Li–LiFePO4 full cells. Moreover, the treated lithium showed improved moisture stability that benefits from the hydrophobicity of the polymer, thus retaining good electrochemical performance after exposure to humid air.

Polymer Alloying of Helical Syndiotactic PMMA with [60]Fullerene-End-Capped Polymers through Inclusion Complex Formation of the Helical Cavity with Fullerene Units

We report a method of polymer alloying by inclusion complex formation of a helical synthetic polymer. By introducing C60 units at the ends of poly(dimethylsiloxane) (PDMS) and utilizing the inclusi...

Tensile Behavior and Phase Separation Structure of Aliphatic Polyketone/Polyamide 6 Polymer Alloy

Tensile Behavior and Phase Separation Structure of Aliphatic Polyketone/Polyamide 6 Polymer Alloy