Efficacy of PU foam materials for scientific investigation in footwear research

2016 ◽  
Vol 36 (3) ◽  
pp. 253-259 ◽  
Author(s):  
Selvaraj Mathivanan ◽  
Ranganathan Mohan ◽  
Bhabendra Nath Das
Keyword(s):  
Dynamic Condition ◽  
High Body Mass Index ◽  
Physical Characteristics ◽  
Foot And Ankle ◽  
Foam Material ◽  
Compression Set ◽  
Therapeutic Benefits ◽  
Pu Foam ◽  
Pu Foams ◽  
High Bmi

Abstract People across the world are primarily concerned with the importance of inserts in footwear in terms of their effectiveness to accomplish therapeutic benefits. Body weight has been implicated as a factor in plantar heel pain, and foot orthoses are commonly used in its conservative treatment and are helpful in reducing symptoms of strain in the fascia during standing and ambulation. It is necessary to investigate the effectiveness of footwear inserts and their impact especially for people with high body mass index (BMI). Hence, research on polyurethane (PU) foams is warranted to identify an ideal material that provides comfort for high-BMI individuals. This article presents details on the physical characteristics of PU foam and its efficacy on functional performances as footwear inserts. PU foam materials have been assessed on various physical characteristics such as density, hardness, compression set followed by resilience, and cushioning behaviors. Of the four densities evaluated, D120 has the highest resilience on static and dynamic conditions. The cushion energy behaviors with respect to walking/running on static and dynamic condition were superior, as they possess better cushioning performance on footwear applications. Hence, the D120 PU foam material is concluded to be the best material for footwear insert for alleviating foot and ankle pain-related problems and for providing therapeutic benefits to high-BMI individuals.

Soy Protein Based Biodegradable Flexible Polyurethane Foam

2010 ◽  
Vol 152-153 ◽  
pp. 1862-1865 ◽  
Author(s):  
Guang Heng Wang ◽  
An Ning Zhou
Keyword(s):  
Soy Protein ◽  
Soy Protein Isolate ◽  
Protein Isolate ◽  
Compression Set ◽  
Pu Foam ◽  
Isocyanate Index ◽  
Biodegradable Polyurethane ◽  
Flexible Polyurethane ◽  
Pu Foams ◽  
Flexible Pu Foam

Soy protein based biodegradable polyurethane (PU) foams were prepared by incorporating soy protein isolate (SPI) into flexible PU foam. The effects SPI content and isocyanate index on the density, resilience, compression set, and biodegradability of the soy protein based PU foams were investigated. The results showed that, soy protein enhanced the compression set, resilience, and biodegradability of PU foams, but increased the density. Furthermore, soy protein can increase open cell proportion in the soy protein based flexible PU foams, and then regulate their properties. The density and compression set value of the soy protein based PU foams decreased with increase in isocyanate index, while the resilience increased. The biodegradability of soy protein based flexible PU foam makes it a prospective material for disposable usage.

scholarly journals Characterization and Evaluation of HGF-Loaded PLGA Nanoparticles in a CCl4-Induced Acute Liver Injury Mouse Model

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Chuxi Lin ◽  
Xueer Wang ◽  
Nuyun Liu ◽  
Qing Peng ◽  
Yang Li ◽  
...  
Keyword(s):  
Liver Injury ◽  
Mouse Model ◽  
Acute Liver Injury ◽  
Redox Homeostasis ◽  
Plga Nanoparticles ◽  
Physical Characteristics ◽  
Sod Activity ◽  
Therapeutic Benefits ◽  
Antioxidant Proteins ◽  
Drug Free

Liver injury can be caused by various harmful factors since the liver is considered the key organ for detoxifying endogenous and exogenous substances. Hepatocyte growth factor (HGF) can regulate redox homeostasis through the expression of antioxidant proteins when the liver is under injury. However, HGF is easily degraded. In this study, we produced three kinds of HGF-loaded poly(lactic-co-glycolic) acid (PLGA) nanoparticles with an initial addition of 2 μg HGF (NPs-HGF-2 μg), 4 μg HGF (NPs-HGF-4 μg), and drug-free nanoparticles (NPs) using the W/O/W emulsion-solvent evaporation method in accordance with our patent. The morphology and physical characteristics were analyzed, and effects of HGF-loaded PLGA nanoparticles on a CCl4-induced acute liver injury mouse model were investigated and compared with HGF solutions. We observed that the morphology and the physical characteristics of the nanoparticles were almost the same, with similar sizes, polydispersity, and zeta potential. HGF-loaded PLGA nanoparticles maintained higher HGF concentrations for a longer period of time in blood and liver tissues. HGF-loaded PLGA nanoparticles increased the SOD activity and GPX levels, decreased the MDA levels in the liver, reduced the necrotic areas of the liver, and decreased the levels of AST, ALT, ALP, T-BIL, BUN, and Scr in blood. In conclusion, our technique for preparing HGF-loaded PLGA nanoparticles was stable and the products were of good quality. HGF-loaded PLGA nanoparticles could provide greater therapeutic benefits on CCl4-induced acute liver injury, including antilipid peroxidation and a reduction in indicator enzymes of liver injury.

scholarly journals Estimated and projected burden of multiple sclerosis attributable to smoking and childhood and adolescent high body-mass index: a comparative risk assessment

2020 ◽  
Author(s):  
Julia Pakpoor ◽  
Klaus Schmierer ◽  
Jack Cuzick ◽  
Gavin Giovannoni ◽  
Ruth Dobson
Keyword(s):  
Risk Factors ◽  
Multiple Sclerosis ◽  
Body Mass Index ◽  
Body Mass ◽  
Early Life ◽  
Time Lag ◽  
Early Adulthood ◽  
High Body Mass Index ◽  
High Body ◽  
High Bmi

Abstract Background Smoking and childhood and adolescent high body-mass index (BMI) are leading lifestyle-related risk factors of global premature morbidity and mortality, and have been associated with an increased risk of developing multiple sclerosis (MS). This study aims to estimate and project the proportion of MS incidence that could be prevented with elimination of these risk factors. Methods Prevalence estimates of high BMI during childhood/adolescence and smoking in early adulthood, and relative risks of MS, were obtained from published literature. A time-lag of 10 years was assumed between smoking in early adulthood and MS incidence, and a time-lag of 20 years was assumed between childhood/adolescent high BMI and MS incidence. The MS population attributable fractions (PAFs) of smoking and high BMI were estimated as individual and combined risk factors, by age, country and sex in 2015, 2025 and 2035 where feasible. Results The combined estimated PAFs for smoking and high BMI in 2015 were 14, 11, 12 and 12% for the UK, USA, Russia and Australia in a conservative estimate, and 21, 20, 19 and 16% in an independent estimate, respectively. Estimates for smoking are declining over time, whereas estimates for high early life BMI are rising. The PAF for high early life BMI is highest in the USA and is estimated to increase to 14% by 2035. Conclusions Assuming causality, there is the potential to substantially reduce MS incidence with the elimination of lifestyle-related modifiable risk factors, which are the target of global public health prevention strategies.

scholarly journals Recovery of Flexible Polyurethane Foam Waste for Efficient Reuse in Industrial Formulations

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1533 ◽  
Author(s):  
Gabriel Kiss ◽  
Gerlinde Rusu ◽  
Francisc Peter ◽  
Ionuț Tănase ◽  
Geza Bandur
Keyword(s):  
Polyurethane Foam ◽  
Atmospheric Pressure ◽  
Air Permeability ◽  
Hydroxyl Number ◽  
Pu Foam ◽  
Flexible Polyurethane Foam ◽  
Flexible Polyurethane ◽  
The Relationship ◽  
Pu Foams ◽  
Glycolysis Process

Ester polyurethane (PU) foam waste was reacted at atmospheric pressure in an autoclave and using microwaves with diethylene glycol (DEG) at different PU/DEG ratios in the presence of diethanolamine as a catalyst to find the glycolysis conditions that allow for the improved recovery of the PU foam waste and enable the recycling of the whole glycolysis product in foam formulations suitable for industrial application. The recycled polyol was characterized by dynamic viscosity, hydroxyl number, water content, and density, while thermal stability was assessed using thermogravimetric analysis. In the PU foam formulation, 1% and 5% of the glycolyzed material was reused. The relationship between the reuse level of the recycled polyol and the physical properties of the foam was thoroughly investigated. It was observed that both hardness and air flow decreased with increasing recycled polyol content, particularly for the polyester type foam, while tensile strength and compression strength increased. Depending on the amount of recycled polyol and catalyst used, polyether-based foams could be obtained with a low air permeability, needed in special applications as sealed foams, or with higher air permeability desirable for comfort PU foams. The results open the way for further optimization studies of industrial polyurethane foam formulations using a glycolysis process without any separation stage.

Preparation of Rigid Flame Retardancy Polyurethane Foam Material with Difficult Combusted Degree

2012 ◽  
Vol 535-537 ◽  
pp. 1151-1157
Author(s):  
Zhen Hui Qiu ◽  
Yuan Bao Sun ◽  
Zhan He Du
Keyword(s):  
Synergistic Effect ◽  
Polyurethane Foam ◽  
Flame Retardancy ◽  
Flame Retardants ◽  
Oxygen Index ◽  
Orthogonal Experiment ◽  
Foam Material ◽  
Pu Foam ◽  
Series Of Experiments

The flame retardants used for the rigid PU foam material were studied systematically in this paper and a series of experiments were carried out to test the oxygen index (OI) of it. The synergistic effect in the different flame retardants also be verified to achieve a well flame retardancy performance. The best ingredients were found out by an orthogonal experiment which can give the PU foam maeterial a difficult combusted degree with the oxygen index higher than 34.

Compression Test and Energy Absorption of Polyurethane/Multi Walled Carbon Nanotubes Foam Composites

2015 ◽  
Vol 819 ◽  
pp. 246-250 ◽  
Author(s):  
A.A. Sinar ◽  
Zainuddin Firuz ◽  
M.A. Nur Azni ◽  
A.Z. Nur Hidayah ◽  
Md Akil Hazizan ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Palm Oil ◽  
Strength Properties ◽  
Pu Foam ◽  
Methylene Diphenyl Diisocyanate ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Pu Foams

This paper describes the effect of multi walled carbon nanotubes (MWCNTs) on the properties, especially the strength properties of rigid polyurethane (PU) foams produced from palm oil based polyol (POP) and methylene diphenyl diisocyanate (MDI). The foam composites in the ratio of 1:1.1 (wt. %) mixed at speed 2000 rpm. The addition of MWCNTs into PU foam are varies from 0 wt. % to 3 wt. %. The properties evaluated were compressive strength, density and energy absorption. Compressive strength of PU foam composites with 0.5% of MWCNTs showed the highest value 1.162 MPa of compressive strength compared to other foam composites. It was proved by modeling displacement nodal magnitude using NX Software (version 8.5). The density was increased 15.69 % with addition of 0.5 % MWCNTs into the PU foam. Increasing the amount of MWCNTs in PU foam was found to improve the energy absorption from 22.89 J for pure PU to 24.53 J for foam composites with 3 % MWCNTs.

Investigation of the Compression Recovery Properties of Polyamide-6 Cellular Solid over the Temperature Range of -5°C to 90°C

2009 ◽  
Vol 417-418 ◽  
pp. 933-936 ◽  
Author(s):  
V.G. Izzard ◽  
C.H. Bradsell ◽  
H. Hadavinia ◽  
V.J. Morris ◽  
P.J.S. Foot ◽  
...  
Keyword(s):  
Compressive Strain ◽  
Polyamide 6 ◽  
Foam Material ◽  
Test Procedures ◽  
Polymeric Foam ◽  
Cellular Solid ◽  
Standard Methods ◽  
Compression Set ◽  
Time Periods ◽  
Over Time

It is a fundamental response of any polymeric foam material to undergo non-recoverable deformation following the application of a defined compressive strain, exacerbated by temperature and humidity. This process is commonly referred to as compression set. The ability to predict recovery after the application of a compressive strain is crucial to both the manufacturers and end users of foam materials. Specific compression set test procedures have been established to quantify the extent of non-recoverable deformation in specific foam types but to date no general predictive approach exists. In this work, compression set (fixed strain) tests were undertaken on a cellular polyamide-6 material at various temperatures (-5°C to 90°C) and the foam recovery monitored over time periods in excess of those dictated by standard methods (ISO 1856 [1]). An empirical formula has been proposed to allow the prediction of recovery after compressive strain, covering recovery periods from 10 minutes to 24 hours (up to 168 hours at 23°C).

scholarly journals Rigid Polyurethane Foam Thermal Insulation Protected with Mineral Intumescent Mat

2014 ◽  
Vol 14 (4) ◽  
pp. 259-269 ◽  
Author(s):  
Mikelis Kirpluks ◽  
Ugis Cabulis ◽  
Viesturs Zeltins ◽  
Laura Stiebra ◽  
Andris Avots
Keyword(s):  
Thermal Conductivity ◽  
Thermal Insulation ◽  
Flame Retardants ◽  
Health Hazard ◽  
Expandable Graphite ◽  
Main Concern ◽  
Insulation Material ◽  
Pu Foam ◽  
Fibre Products ◽  
Pu Foams

Abstract One of the biggest disadvantages of rigid polyurethane (PU) foams is its low thermal resistance, high flammability and high smoke production. Greatest advantage of this thermal insulation material is its low thermal conductivity (λ), which at 18-28 mW/(m•K) is superior to other materials. To lower the flammability of PU foams, different flame retardants (FR) are used. Usually, industrially viable are halogenated liquid FRs but recent trends in EU regulations show that they are not desirable any more. Main concern is toxicity of smoke and health hazard form volatiles in PU foam materials. Development of intumescent passive fire protection for foam materials would answer problems with flammability without using halogenated FRs. It is possible to add expandable graphite (EG) into PU foam structure but this increases the thermal conductivity greatly. Thus, the main advantage of PU foam is lost. To decrease the flammability of PU foams, three different contents 3%; 9% and 15% of EG were added to PU foam formulation. Sample with 15% of EG increased λ of PU foam from 24.0 to 30.0 mW/(m•K). This paper describes the study where PU foam developed from renewable resources is protected with thermally expandable intumescent mat from Technical Fibre Products Ltd. (TFP) as an alternative to EG added into PU material. TFP produces range of mineral fibre mats with EG that produce passive fire barrier. Two type mats were used to develop sandwich-type PU foams. Also, synergy effect of non-halogenated FR, dimethyl propyl phosphate and EG was studied. Flammability of developed materials was assessed using Cone Calorimeter equipment. Density, thermal conductivity, compression strength and modulus of elasticity were tested for developed PU foams. PU foam morphology was assessed from scanning electron microscopy images.

scholarly journals Engagement with and outcomes of a Midwifery-led intervention group for pregnant women of high body mass index

2016 ◽  
Vol 9 (3) ◽  
pp. 120-125 ◽  
Author(s):  
Sarah R Chwah ◽  
Amanda Reilly ◽  
Beverley Hall ◽  
Anthony J O’Sullivan ◽  
Amanda Henry
Keyword(s):  
Body Mass Index ◽  
Pregnant Women ◽  
Body Mass ◽  
Intervention Group ◽  
Group Versus ◽  
High Body Mass Index ◽  
Breastfeeding Initiation ◽  
Retrospective Case ◽  
Significant Difference ◽  
High Bmi

Aims To compare pregnancy care, maternal and neonatal outcomes of women with Body Mass Index (BMI) >30 enrolled in a Weight Intervention Group versus other models of antenatal care. Methods Retrospective, case-control study of mothers with BMI >30 managed with a specialised programme versus age-matched women enrolled in standard models of care. Results One thousand, one hundred and fifteen of 9954 pregnant women with singleton pregnancies, had a BMI >30, of whom 9.6% enrolled in the intervention group. Compared to controls, the intervention group had superior implementation of local high BMI guidelines, including; nutritional /weight gain advice (86% vs. 46%, p < 0.001), regular weighing (80% vs. 33%, p < 0.001), lactation consultant referrals (8% vs. 1%, p = 0.02), third trimester anaesthetic review and ultrasound (50% vs. 20.9%, p = 0.04 and 55% vs. 43%). Initiation of breastfeeding was higher in the intervention group (100% vs. 90%, p = 0.001). No significant difference was noted in Caesarean rate (30% vs 32%) and birthweight (3538 g vs 3560 g). Conclusions Women with high BMI enrolled in a specialised antenatal management programme received increased care, and had superior breastfeeding initiation rates. However, engagement was poor, and no significant differences were noted in antenatal or postnatal complications, mode of birth or neonatal outcome.

scholarly journals Treatment of type IV Pipkin fracture in patients with a high BMI via hip arthroscopy-assisted surgery: a case report

2020 ◽  
Author(s):  
Shan-Ling Hsu ◽  
Chung-Yang Chen ◽  
Chi-Hsiang Hsu
Keyword(s):  
Hip Arthroscopy ◽  
High Body Mass Index ◽  
Open Reduction Internal Fixation ◽  
Fracture Pattern ◽  
Surgical Approaches ◽  
Term Outcome ◽  
Joint Congruency ◽  
Type Iv ◽  
Fracture Dislocations ◽  
High Bmi

Abstract Pipkin type IV femoral head (FH) fracture–dislocations are usually treated via open surgery. There are many surgical approaches for the treatment of this difficult fracture depending on the fracture pattern. Obesity presents another challenging problem in surgical treatment and sometimes leads to a poorer outcome. We discuss herein a patient of a high body mass index (BMI) with a Pipkin type IV FH fracture who underwent open reduction internal fixation (ORIF) of anacetabular fracture with reconstruction plates and hip arthroscopy-assisted fixation of the FH fracture with two Herbert screws via the posterior approach. The intra-articular osteochondral loose bodies were excised by hip arthroscopy simultaneously. The joint congruency and screw positions were checked during surgery by arthroscopy. After 6 months, clinical and computed tomography (CT) follow-ups showed excellent results. The patient of a high BMI recovered immediately and had a satisfactory short-term outcome after hip arthroscopy-assisted surgery. We concluded that hip arthroscopy-assisted surgery is a viable option for the treatment of Pipkin type IV FH fracture–dislocations.

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