Underwriters Laboratories Research Articles

Simultaneously enhance the fire safety and mechanical properties of PLA by incorporating a cyclophosphazene-based flame retardant

Abstract The application of poly(lactic acid) (PLA) has been limited in flame-retardant field, and flame-retardant modification usually deteriorates its mechanical properties. In this study, a reactive flame-retardant hexa(ethylene oxide)-cyclotriphosphazene (HCCP-EP) was synthesized and used to improve the fire retardancy of PLA. As a result, the limiting oxygen index of PLA increased from 19.5% to 27.3% with an addition of 3 wt% HCCP-EP, and the PLA/HCCP-EP blend reached to underwriters laboratories (UL)-94 V-0 rating. The cone calorimeter test results showed that the peak heat release rate and total heat release of PLA decreased by 12.6% and 18.5%, respectively. Interestingly, the tensile strength of PLA increased slightly after the incorporation of HCCP-EP. The improved mechanical properties are ascribed to the fine dispersion of HCCP-EP and the coupling reaction between the epoxy groups of the HCCP-EP and the terminal groups of PLA during the melt processing.

Effects of a symmetrical inorganic-organic monomer on the flame retardancy and mechanical properties of polyethylene terephthalate copolymers

In this paper, a kind of symmetric functionalized monomer is presented, and a polyester with flame retardancy and mechanical properties is obtained. Magnesium hydroxide was modified with phenylphosphonic acid to give a novel inorganic–organic monomer (MH-PPOA) with intrinsic flame retardancy. MH-PPOA was incorporated into the main chain of polyethylene terephthalate (PET) in varying amounts (n, wt% relative to terephthalic acid) to give a series of co-polyesters (MH-PPOAn-co-PET), and the effects of the monomer on their flame retardancy and mechanical properties were determined. The structure and morphology of the hybrid monomer was confirmed by Fourier transform infrared spectroscopy, and scanning electron microscopy, and its successful introduction into the polyester chain of PET was verified by proton nuclear magnetic resonance spectroscopy. The thermal characteristics, flame retardancy and burning behavior of the synthesized copolymers were evaluated by differential scanning calorimetry, thermogravimetric analysis, measurement of the limiting oxygen index (LOI), Underwriters Laboratory vertical burning (UL-94) test, and cone calorimetry. The mechanical properties were measured by tensile testing. This study provides a new direction for the introduction of intrinsic flame retardants anddemonstrates that the incorporation of a symmetrical phenylphosphonic acid modified magnesium hydroxide monomer can also improve the mechanical properties of the PET copolymer.

Multi-Layered Numerical Model Development of a Standard Cylindrical Lithium-Ion Battery for the Impact Test

For safety issues in lithium-ion batteries (LIBs), international standards and regulations for various abusive environments have been developed, and UL1642 in Underwriters Laboratories (UL) currently covers electrical, mechanical, environmental, and fire exposure tests. An impact test is one of mechanical abuse tests in UL1642, which aims to determine the safe prevention of fire or explosion. As the energy density of a lithium-ion battery is continuously increasing, it is difficult to pass the regulation. Therefore, it is necessary to predict failure mode due to an internal short circuit in developing high-capacity cells. For a sudden and measured mechanical force, we speculate that damage to a separator consisting of LIBs makes the battery experience an exothermic phenomenon due to an internal short circuit because a separator is a key component for preventing the electrical contact between two electrodes. Therefore, if we can find mechanical stresses of each component in LIBs, we can evaluate whether each component is severely damaged or not. In the present study, we propose a finite element model consisting of a multi-layered structure, which will permit us to assess the possible onset location of the short circuit, and to predict the sequence of failure at a cell level. We applied the proposed method to a cylindrical cell, and the accuracy of the model was verified through the comparison of the experiment results. Additionally, simulation results showed that it is possible to track mechanical stress variations of each component progressively. Furthermore, we performed the numerical experiment evaluating the thickness effect of a center-pin. We expect the proposed finite element model to be used in order to devise cell level abuse-tolerant design from a mechanical point of view before conducting mechanical abuse tests as part of the product development process.

Separating facts and evaluation: motivation, account, and learnings from a novel approach to evaluating the human impacts of machine learning

In this paper, we outline a new method for evaluating the human impact of machine-learning (ML) applications. In partnership with Underwriters Laboratories Inc., we have developed a framework to evaluate the impacts of a particular use of machine learning that is based on the goals and values of the domain in which that application is deployed. By examining the use of artificial intelligence (AI) in particular domains, such as journalism, criminal justice, or law, we can develop more nuanced and practically relevant understandings of key ethical guidelines for artificial intelligence. By decoupling the extraction of the facts of the matter from the evaluation of the impact of the resulting systems, we create a framework for the process of assessing impact that has two distinctly different phases.

Development and characterization of flame retardant property in flexible polyurethane foam

Polyurethane foam (PF) is an essential polymer which is widely used in everyday applications either directly or indirectly by the fast moving world. By changing the composition of polyol and isocyanate, these foams can be classified into rigid polyurethane foams (PUFRs) and flexible polyurethane foams (PUFFs). Due to the open cell structure, low decomposition temperature of the monomers, polyurethane foams (PFs) are easily prone to flammability which can prove to be hazardous to its end users. In this present study, a list of potential flame retardants (FRs) such as expandable graphite (EG), magnesium hydroxide (MGH), nano-titanium dioxide (NTD), organo-montmorillonite (OMMT), and MGH with OMMT, EG as a synergetic combinations were used. EG was prepared at the laboratory scale and its morphology was analyzed by scanning electron microscope (SEM). The SEM substantiates the formation of worm like structure in EG which helps in suppressing the growth of flame. Various testing methods were used to characterise the generated PUFFs, including morphology using optical microscope (OM), functional groups using Fourier infrared spectroscopy (FTIR), and flame retardant (FR) property using an Underwriters laboratories (UL) 94 horizontal burning (HB). An OM image confirms the formation of open cell structure which shows PUFF. The peak in the range 2270 cm−1 and 2240 cm−1 was not observed in the FTIR spectra for any of the PUFF samples prepared. This demonstrates and proves that the isocyanate utilised is totally transformed to PUFF, implying that urea and urethane linkages are formed with the addition of polyol and fillers. Among all PUFFs, the UL 94 HB test affirms that the combination of EG + MGH has the best FR property with 0.27 mm/s rating because of the synergistic effect. This confirms the suitability of PUFF in applications when compared to the other chosen in the present investigation.

PREPARATION OF IRON- REDUCED GRAPHENE OXIDE/ EPOXY RESIN COMPOSITE AND ITS FLAME RETARDANCY AND THERMAL STABILITY

In order to reduce flammability, smoke release and enhance thermal stability of epoxy resin (EP), iron powder is mixed with graphene oxide/ epoxy resin (GO/EP) composite by mechanical blending. The combustion performance of composite material is investigated through limiting oxygen index (LOI), Underwriters Laboratory (UL)-94 test, and cone calorimeter test (CCT). Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) and scanning electron microscope (SEM) are also used to explore the mechanism of flame retardancy and smoke suppression. Results show that, with the addition of 0.5% mass fraction of GO and the corresponding iron powder combination (EP3 sample), the LOI value can achieve 32.5% while reaching the UL-94 V0 rating. Compare with EP0, the peaks of heat release rate, smoke production rate, and smoke factor values of EP3 are decreased by 42%, 60%, and 50%, respectively. The char and TG-FTIR data of EP3 reveal that it has a more compact structure, good thermal stability, and produce fewer toxic gases and smoke. Reduction of GO could inhibit the degradation of EP, and iron catalyzes the formation of carbonaceous char on the surface. Thus, the thermal stability and flame retardancy of EP are improved significantly. This study provides a suitable way to prepare graphene/EP composites that contain iron catalyst and can be extended to the industrial manufacture of flame retardant polymer composites. Keywords: iron powder; epoxy resin; graphene oxide; flame retardant; thermal stability

Flame retardant rigid polyurethane foam composites based on iron tailings and aluminum phosphate: A novel strategy for utilizing industrial solid wastes

AbstractTo widen the application field of iron tailings (ITs) and explore ITs potential use‐value, ITs and aluminum phosphate (AHP) were introduced to prepare flame‐retardant rigid polyurethane foam (FR‐RPUF) composites. The chemical composition and mineral composition of ITs were investigated by X‐ray diffraction, X‐ray fluorescence. The flame retardancy, thermal stability, combustion performance and gas‐phase products of FR‐RPUF composites were investigated by limiting oxygen index, underwriters laboratories vertical burning test (UL‐94), thermogravimetry (TG), cone calorimetry and thermogravimetric‐infrared spectrometry (TG‐FTIR). TG confirmed that ITs could effectively improve the thermal stability of FR‐RPUF composites at high temperature. Cone calorimetry implied that ITs could significantly reduce heat release and toxic smoke release and thus improve the fire safety of the composites. TG‐FTIR indicated that ITs effectively reduced the release intensity of hydrocarbons, aromatic compounds, CO, isocyanates and esters. Scanning electron microscope and Raman spectra showed ITs could improve the compactness and graphitization degree of the char residues for FR‐RPUF composites.

Synergistic properties of microencapsulated intumescent flame retardant-organically modified montmorillonite/ethylene-vinyl acetate copolymer composites

Flame retardant ethylene-vinyl acetate (EVA) composites were prepared by combination of microencapsulated intumescent flame retardants-ammonium polyphosphate (APP)-pentaerythritol (PER) and organically modified montmorillonite (OMMT). The microencapsulated APP (MCAPP)-microencapsulated PER (MCPER)-OMMT/EVA composites were further characterized through XRD and TEM, confirming OMMT sheets are well dispersed in the matrix as exfoliated or intercalated nanocomposite state. Limiting oxygen index (LOI), TGA, underwriters laboratories 94 vertical burning (UL-94), cone and smoke density test results indicate the synergistic flame retardancy effect between MCAPP-MCPER and OMMT in MCAPP-MCPER-OMMT/EVA composites. Replacing the same amount of MCAPP-MCPER with 3wt% OMMT could improve the LOI value of the MCAPP-MCPER-OMMT/EVA composites from 25.5vol% to 29.5vol%. The UL-94 rating increases from V-2 to V-0. The char residue of MCAPP-MCPER-OMMT/EVA composites is improved from 14.5wt% to 15.9wt% and the smoke density significantly decreases from 154.7 g/s to 97.5 g/s. Besides, the mechanical property of MCAPP-MCPER-OMMT/EVA composites was tested by universal testing machine and dynamic thermomechanical analysis (DMA), the result shows that the flame-retardant MCAPP-MCPER-OMMT/EVA composites has better mechanical properties.

A Study on Circular Economy Material Using Fish Scales as a Natural Flame Retardant and the Properties of Its Composite Materials

Fish scales (FSs) are fishery wastes that can cause environmental pollution. This study aimed to solve this environmental problem. FSs were used as a flame retardant for polymer materials, making them valuable. Fish scales were combined with a commercial flame retardant, ammonium polyphosphate (APP), through synergistic effects to reduce the amount of commercial flame retardant. The use of FSs conforms to the concept of a circular economy and lowers costs by reducing the consumption of APP. Thermogravimetric analysis (TGA), integral procedural decomposition temperature (IPDT), pyrolysis kinetics, limiting oxygen index (LOI), the Underwriters Laboratories 94 (UL94) flammability test, scanning election microscopy, Raman spectroscopy, and energy-dispersive X-ray spectroscopy were used to determine the thermal properties, flame retardant properties, flame retardant mechanism, char morphology, and composition of the composites. The TGA results indicated that the addition of 40% flame retardant raised the char residue from 16.45 wt.% (pure EP) to 36.07 wt.%; IPDT from 685.6 °C (pure EP) to 1143.1°C; LOI from 21% (pure EP) to 30%; and UL94 classification from fail (pure EP) to V-0. These results suggest an increase in char residue, which indicates better protection of the polymer matrix material. The improvements in IPDT, LOI, and UL94 classification, which indicate greater thermal stability, lower flammability (from flammable to fireproof), and higher flammability rating (from fail to V-0), respectively, suggest that the composite material has favorable thermal properties and is less inflammable.

Charge and discharge profiles of repurposed LiFePO4 batteries based on the UL 1974 standard

Owing to the popularization of electric vehicles worldwide and the development of renewable energy supply, Li-ion batteries are widely used from small-scale personal mobile products to large-scale energy storage systems. Recently, the number of retired power batteries has largely increased, causing environmental protection threats and waste of resources. Since most of the retired power batteries still possess about 80% of their initial capacity, their second use becomes a possible route to solve the emergent problem. Safety and performance are important when using these second-use repurposed batteries. Underwriters Laboratories (UL), a global safety certification company, published the standard for evaluating the safety and performance of repurposed batteries, i.e., UL 1974. In this work, the test procedures are designed according to UL 1974, and the charge and discharge profile datasets of the LiFePO4 repurposed batteries are provided. Researchers and engineers can use the characteristic curves to evaluate the quality of the repurposed batteries. Furthermore, the profile datasets can be applied in the model-based engineering of repurposed batteries, e.g., fitting the variables of an empirical model or validating the results of a theoretical model.

Flame retardant rigid polyurethane foam composites based on microencapsulated ammonium polyphosphate and microencapsulated expanded graphite

Microencapsulated ammonium polyphosphate (GMAAPP) and microencapsulated expanded graphite (PUEG) were prepared by in situ polymerization with glycidyl methacrylate (GMA) and polyurethane as the shell material respectively. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and thermogravimetry (TG) were used to characterize GMAAPP and PUEG. The results confirmed the successful fabrication of GMAAPP and PUEG. On this basis, a series of flame-retardant rigid polyurethane foam composites were prepared with GMAAPP and PUEG loading by the one-step water-blown method. The flame retardancy, mechanical properties, thermal insulation, and thermal stability of RPUF/GMAAPP30, RPUF/PUEG30, and RPUF/GMAAPP20/PUEG10 composites were investigated by limiting oxygen index (LOI), Underwriters Laboratories vertical burning test (UL-94), TG, thermal conduction and density test. The results showed that the thermal stability at the high temperature of RPUF composites can be improved by the addition of GMAAPP and PUEG. SEM test confirmed significantly enhanced compatibility between the microencapsulated flame retardant particles and RPUF matrix, which obviously improved the integrity of the cell structure. RPUF/GMAAPP30, RPUF/PUEG30 and RPUF/GMAAPP20/PUEG10 exhibited LOI of 22.3 vol%, 25.3 vol%, 24.6 vol% with all composites passed V-0 rating in UL-94 test. The physical performance test indicated that RPUF/GMAAPP20/PUEG10 exhibited thermal conductivity of 0.0395 W/m·K and compressive strength of 0.292 MPa, which possessed the best comprehensive physical performance. Char residue analysis suggested the combination of GMAAPP and PUEG increased graphitization degree and compactness of char residues for RPUF composites, thus effectively improving the fire safety of the composite.

Physico‐mechanical and Flammability Properties of Cyrtostachys renda Fibers Reinforced Phenolic Resin Bio-composites

The aim of this study is to investigate the effect of fiber length and loading on physico-mechanical and flammability properties of Cyrtostachys renda (CR) fiber-reinforced phenolic composites. Waste based Cyrtostachys renda (CR) fiber reinforced phenolic resin derived from cashew nut shell liquid (CNSL), bio-composite has been studied. Composites with alkali treated CR fiber length in the ranges of 1.18–0.6, 0.6–0.3 and less than 0.3 mm in 20 wt% and 40 wt% based on weight of phenolic resin were prepared by hot compression. Flammability, water absorption, tensile/flexural/impact tests were carried out on the composites and also characterized by scanning electron microscope (SEM). Composite containing 40 wt% fiber of length less than 0.3 mm has the highest tensile and flexural strengths of 34.27 MPa and 65 MPa respectively. It has been found that water absorption and thickness swelling increases as weight % of fiber increases. For the Underwriters Laboratories (UL 94), all the neat phenolic and addition with CR fiber exhibited NC and H-B classifications for vertical and horizontal respectively, however Limiting Oxygen Index (LOI), of neat phenolic dropped from 29.33 to 26 and 25 for 20 wt% and 40 wt% respectively. Morphology of the tensile fractured laminates revealed that micro pores in fibers are filled with phenolic resin, hence increases the interfacial bonding between fiber and the matrix. The research findings provision that CR fiber reinforced phenolic composites is potential to be utilized as green and biodegradable composites for interior components of automotive and aviation industry.

Flame retardant transparent films of thermostable biopolyimide metal hybrids

The development of flame retardant transparent films is important for electric devices and building materials it but it is still a challenge. Herein, flame retardant films having high optical transparency were developed from the amino acid-based biopolyimide (BPI) salt with aluminum (BPI-COOAl) and copper ions (BPI-COOCu). The microscale combustion calorimetry analysis revealed that for BPI-COOAl, the total heat released (THR) and peak heat released rate were 4.5 W/g and 18.9 kJ/g, respectively. These values were lower than those of its precursors and BPI-COOCu. BPI-COOAl was rated V-0 for the Underwriters Laboratories vertical burning standard test. The polymer also retained a high transparency of more than 80% transmittance at a wavelength of 450 nm. The tensile strength was also preserved at 63.7 MPa. For BPI-COOCu, 14.6 kJ/g THR and 47.1 MPa tensile strength were observed. When a colorful ion such as Cu was used, BPI-COOCu became a flame retardant film that was a green filter. The char formation of Al₂O₃ and Cu₂O in their respective polymer complexes was deduced as the main flame suppression mechanism. The present films of biopolyimide salts are advantageous in showcasing the balance of different essential material properties such as flame retardancy, thermo-mechanical stability, and transparency.

High-fire-safety thermoplastic polyester constructed by novel sulfonate with benzimidazole structure

The flammability of thermoplastic polyesters and the subsequent heavy smoke and severe melt drips formed after ignition are the main obstacles hindering their widespread application. In this study, a novel ionic monomer containing sulfonate and benzimidazole was synthesized and incorporated into the main chain of poly(ethylene terephthalate) (PET, used as a model thermoplastic polyester) by melt copolymerization. The synergetic effect of ionic aggregation and carbonization endowed the obtained copolyester with high melt viscosity and excellent char-forming ability at high temperatures. The copolyester having a monomer content of 8 mol.% easily achieved the Underwriters Laboratories Inc 94 (UL-94) V-0 flammability rating without dripping and the limiting oxygen index value reached 33.0 vol.%. In addition, the total smoke production, peak heat release rate, and maximum CO production decreased by 45.2%, 60.5%, and 75.0%, respectively, compared with those of PET. In addition, the copolyester was spinnable, and showed greater adsorption efficiency (99.6%) for a cationic dye from solution compared to PET (6.5%), demonstrating the excellent affinity of the copolyester for the cationic dye. The obtained inherently fire-safe PET copolyester has great potential for applications in flame retardant textiles, artwork base materials, and decorative materials for transportation applications.

Flame retarded rigid polyurethane foam composites based on gel-silica microencapsulated ammonium polyphosphate

Microencapsulated ammonium polyphosphate (SiAPP) was prepared by sol-gel method with gel-silica as the shell material. And also, SiAPP was characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), which confirmed the successfully fabrication of SiAPP. Furthermore, 30 php (parts per hundreds of polyol) SiAPP was introduced to prepare rigid polyurethane foam/microcapsulated ammonium polyphosphate composites (RPUF/SiAPP30). Flame retardancy, water resistance, physical properties and thermal stability of RPUF/SiAPP composites were compared with virgin RPUF and RPUF/APP composites. The results showed that RPUF/SiAPP30 which possessed excellent flame retardancy. Even after being immersed in water for 15 days, the underwriters laboratories vertical burning test (UL-94) of RPUF/SiAPP30 could pass V-1 rating with the limiting oxygen index (LOI) of 21.8 vol%, which was better that of RPUF/APP30. Compressive strength of RPUF/SiAPP30 was 0.292 MPa, which was 12.3% higher that of RPUF/APP30. SEM and Raman spectra confirmed that RPUF/SiAPP30 possessed more compact char residue with higher thermal resistance, which could inhibit mass and heat transmission in combustion. Consequently, a possible gas-solid flame-retardant mechanism of RPUF/SiAPP composite was proposed.

Making Microwave Oven Doors Child Resistant to Protect Young Children From Severe Scalds.

Most severe child scalds in the United States involve food and beverages. The wide variety of burn mechanisms, however, makes prevention challenging. Over the past 15 years, we have worked toward protecting young children from 1 specific mechanism: children opening microwave oven doors themselves and spilling the heated contents, resulting in often severe scalds. In our published research, we documented the frequency and severity of these cases and the vulnerability of young toddlers to be burned in this way. We have presented our findings and ideas for prevention at multiple national meetings and enlisted college engineering students to design microwave doors that would thwart a young child from opening them. In 2017, we became active members of a national task group convened by Underwriters Laboratories to address this issue, and two authors became voting members on the Underwriters Laboratories Standards Technical Panel for microwave ovens. We worked with microwave manufacturers and others for >1 year to address concerns of the industry, including those related to potential impacts on older adults. This effort resulted in the task group proposing a change in the standard, requiring "two distinct actions" to open the door of a microwave oven. On September 17, 2018, the panel voted to pass the measure, which will require child-resistant doors for all new microwave ovens in 2023. This report highlights how research can inform and support child injury prevention advocacy. Children will now be protected from this type of scald as microwaves with child-resistant doors replace current models.

An Assessment of Research Priorities to Dampen the Pendulum Swing of Burn Resuscitation.

On June 17 to 18, 2019, the American Burn Association, in conjunction with Underwriters Laboratories, convened a group of experts on burn resuscitation in Washington, DC. The goal of the meeting was to identify and discuss novel research and strategies to optimize the process of burn resuscitation. Patients who sustain a large thermal injury (involving >20% of the total body surface area [TBSA]) face a sequence of challenges, beginning with burn shock. Over the last century, research has helped elucidate much of the underlying pathophysiology of burn shock, which places multiple organ systems at risk of damage or dysfunction. These studies advanced the understanding of the need for fluids for resuscitation. The resultant practice of judicious and timely infusion of crystalloids has improved mortality after major thermal injury. However, much remains unclear about how to further improve and customize resuscitation practice to limit the morbidities associated with edema and volume overload. Herein, we review the history and pathophysiology of shock following thermal injury, and propose some of the priorities for resuscitation research. Recommendations include: studying the utility of alternative endpoints to resuscitation, reexamining plasma as a primary or adjunctive resuscitation fluid, and applying information about inflammation and endotheliopathy to target the underlying causes of burn shock. Undoubtedly, these future research efforts will require a concerted effort from the burn and research communities.

An Evaluation of the Firefighting Effectiveness of Fluorine-Free Foams

An experimental program was conducted to assess the firefighting capabilities (extinguishment and burnback times) of five commercially available, Underwriters Laboratories listed (UL 162) fluorine-free foams (FFFs) [three alcohol resistant (AR) and two hydrocarbon approved (H)] and one short chain C6 aqueous film forming foam (AFFF) formulation (for baseline) as a function of application rate (gpm/ft2) and foam discharge density (gal/ft2) for a range of test parameters including foam quality/aspiration (air-aspirated and non-air-aspirated), fuel type [heptane, gasoline (MIL-SPEC and E10), and IPA], water type (fresh and salt) and fuel temperature (ambient and elevated). To summarize the results, the baseline C6 AR-AFFF demonstrated consistent/superior firefighting capabilities throughout the entire test program under all test conditions and test fuels. The FFFs did well against heptane but struggled against some of the scenarios conducted with IPA and gasoline (both MIL-SPEC and E10), especially when the foam was discharged with a lower foam quality/aspiration. From an application rate perspective, the FFFs typically required between 1.5 and 3 times the application rates to produce a comparable performance as the baseline AR-AFFF for the range of parameters included in this assessment. From an extinguishment density perspective, the extinguishment densities for the FFFs were typically 2–7 times greater than the baseline AR-AFFF and were determined to be both manufacturer and fuel type dependent. The three major findings of the study include: foam quality/aspiration effects on the firefighting capabilities of FFFs, variations in extinguishment difficulty associated with fuel type and variations in capabilities between listed FFFs in general.

Обзор опыта работы организаций по оценке соответствия продукции в Канаде

A review of the international practice of conformity assessment and accreditation organizations allows us to study current trends in this area and use best practices to improve the Russian system for assessing the conformity of products used in the system of main pipeline transportation of oil and petroleum products. The purpose of this article is to provide an overview of the current experience of conformity assessment and accreditation organizations in Canada. The features of the national system conformity assessment have been analyzed. It was noted that it has a centralized nature, while the federal nonprofit organization – Standards Council of Canada, which has significant authority in the country and is recognized abroad, has the exclusive authority for accreditation. Structure and features of the work of the leading organizations of the system conformity assessment in Canada have been reviewed: Standards Council, Canadian Standards Association, Underwriters Laboratories of Canada, and QPS. It was concluded that that Canada has created a unified State system of conformity assessment, based on both international and national standards, as well as on the documents of certification organizations.

Development and characterization of multifunctional carbon fabric‐reinforced polymer composites incorporated with inorganic flame retardants

AbstractCarbon fabric‐reinforced polymer (CFRP) composites were incorporated with novel, environment‐friendly and, low‐cost inorganic flame‐retardant (FR) materials. Synergistic properties of potash alum (KA) and magnesium hydroxide (MH) were obtained by infusing these materials in the carbon woven fabric with diglycidial ether of bisphenol‐A epoxy (EP) matrix through resin infusion technology. Composite samples EP80%MH20% and EP80%MH15%KA5% showed Underwriter Laboratories 94 (UL94) V‐2 rating, EP80%MH10%KA10% and EP80%MH5%KA15% showed UL94 V‐1 rating, and EP80%KA20% showed UL94 V‐0 rating. Flame retardancy of EP was improved with increasing concentration of KA up to UL94 V‐0 while a high concentration of MH improved flame retardancy only up to UL94 V‐2 rating, which is not suitable for the material. Flexural modulus and flexural strength of EP were decreased with increasing concentration of KA and MH because both FR created the distance between the EP chains and hence imparted ductility. Thermogravimetric analysis showed an increase in char residue with increasing KA concentration. The char residue of EP100% (without FR materials) was 16.5 wt%, which increased to 71.2 wt% for EP80%KA20%. CFR samples were prepared with the given FR materials and it was seen that reduction in mechanical properties was compensated with the help of CFRP.