bluuebunny/crossref_metadata_2025 huggingface dataset:
Foreign Investment in Hospital Sector in India
Authors: Hooda Shailender Kumar
Published: July 2017

This study examines the status and trends of foreign investment inflow in Indian hospital sector and highlights emerging issues. During the liberalized foreign investment regime between 2000 and 2014, a large number of foreign players have been focusing on Indian hospital sector and have enlarged their presence through partnership and investment in joint venture projects. Though foreign investment inflow in hospitals has increased to almost hundred times, it constitutes a small share within total financing of health care. It is the long-term domestic borrowing that predominates. The overall growth in foreign investment has largely been for providing super-speciality and tertiary care services particularly in the metropolitan cities, while investment for primary and secondary cares, clinical research, drugs development, diagnostic services and rural area remained negligible. The study argues that the private investment can play a complementary role in providing tertiary and speciality care services particularly in the untapped hospital market and it should not be considered as the substitute of public provisioning of health care services. The role of the government is warranted to provide cost-effective cares to general population across remotest area of the country.
An in-Service Program With Teachers of Gifted Children
Authors: Graves Myrna , Thompson Jack
Published: July 2017

In-service workshops focusing on an individualized child study approach brings about an increment in the teacber's understanding of the gifted.
Aspects of Intelligence in Gifted Preschoolers
Authors: Landig Hans-J. , Naumann Theodor F.
Published: July 2017

Stanford-Binet results for 36 gifted children of preschool age were classified into categories according to Guilford's Structure-of-Intellect (SI) model. Four of five operations categories were considere d and the levels of relative magnitude b etween the different factors compared. Also examined were changes within t he same fac tor over a two year span. Greatest variability b etween SI factors oc curred at younger age groups. Three factors showed a relative decline over the two year test span despite steady Stanford-Binet IQ levels.
Well-being and perceptions of everyday activities among those who attend community-based day centres for people with mental illness in Sweden – Does an immigrant background make a difference?
Authors: Pooremamali Parvin , Eklund Mona
Published: July 2017

Background:

Community-based day centres (CBDCs) for people with mental illness are a common service for both people with an immigrant background and native Swedes.

Aim:

The aim was to compare CBDC attendees with an immigrant background with attendees who were native Swedes in terms of well-being and perceptions of everyday activities and investigate whether ethnic background could predict these factors.

Methods:

Attendees at nine CBDCs were invited to participate. In all, 56 with an immigrant background and 69 native Swedes completed self-report questionnaires that addressed various aspects of well-being and everyday activities.

Results:

Attendees with an immigrant background had a worse situation regarding perceived self-esteem, empowerment and satisfaction with everyday activities. In multivariate logistic regression analyses, ethnic background only became a significant predictor in regard to empowerment. Quality of life and activity level were of importance for satisfaction with everyday activities. Empowerment and self-esteem mutually influenced each other.

Conclusion:

Having a mental illness and an immigrant background may infer a particular risk for low empowerment. The mental health services and society at large should consider measures for adjusting the support to this group, including an analysis of how environments and contexts may act as barriers to activity enrichment and culturally congruent support.
Stigma-related mental health knowledge and attitudes among primary health workers and community health volunteers in rural Kenya
Authors: Mutiso Victoria N , Musyimi Christine W , Nayak Sameera S , Musau Abednego M , Rebello Tahilia , Nandoya Erick , Tele Albert K , Pike Kathleen , Ndetei David M
Published: July 2017

Background:

The study was conducted in rural Kenya and assessed stigma in health workers from primary health facilities.

Aims:

This study compared variations in stigma-related mental health knowledge and attitudes between primary health workers (HWs) and community health volunteers (CHVs).

Methods:

Participants ( n = 44 HWs and n = 60 CHVs) completed the self-report Mental Health Knowledge Schedule and the Reported and Intended Behavior Scale, along with sociodemographic questions. Multiple regression models were used to assess predictors of mental health knowledge and stigmatizing behaviors.

Results:

HWs had significantly higher mean mental health knowledge scores than CHVs, p < .001, and significantly higher mean positive attitudes scores than CHVs, p = .042. When controlling for relevant covariates, higher positive attitudes was the only significant predictor of higher mental health knowledge, and self-rating of sense of belonging to the community and mental health knowledge remained the main predictors of positive attitudes.

Conclusion:

Results suggest that stigma-related mental health knowledge and attitudes are associated, and interventions should target these areas with health workers. There is scope for intervention to increase knowledge and positive attitudes for individuals who feel a strong sense of community belonging. Future studies should test feasible ways to reduce stigma in this population.
Parameters Affecting Extrusion Foaming of PET by Gas Injection
Authors: Xanthos M. , Dey S. K. , Zhang Q. , Quintans J.
Published: July 2017

The rheological properties of conventional PET resins are not particularly suitable for low density extrusion forming with physical blowing agents, and as a result modified resins with higher melt viscosity and elasticity are often used. In this work, parameters affecting the monolayer flat sheet extrusion of foams having variable densities (from about 1.2 to 0.2 g/cc) are presented. Unmodified and chemically modified resins with different melt viscoelastic properties are used. The effects of variables such as type and concentration of atmospheric gases, resin rheology and choice of process conditions are related to product characteristics, including density, crystallinity and thermoformability.
Melt Extruded Open-Cell Microcellular Foams for Membrane Separation: Processing and Cell Morphology Relationship
Authors: Huang Quan , Seibig Bernd , Paul Dieter
Published: July 2017

This paper presents an experimental study on the manufacture of microcellular polycarbonate in a designed co-rotating twin-screw extrusion system using CO2 as a blowing agent. Open-cell microcellular polycarbonate foams in the form of hollow fiber were produced with a cell density on the order of 109-1010 cell/cm3 and an average cell size in the range of 5-10 μm. The effects of the processing conditions on the cell morphology and the cell-opening technique are described.
Diffusivity, Solubility and Permeability of Blowing Agents in Polystyrene at Low Pressures
Authors: Park Chung P.
Published: July 2017

Transport properties of polystyrene to organic blowing agents were studied by applying the sorption method to both submicron-thickness cell walls and standard blown films. In addition to the benefit of having greatly shortened test times, the use of cell walls revealed that blowing agents diffused more slowly and dissolved less in the cell walls than in the much thicker films. The diffusion and solubility coefficients of blowing agents were found to be pressure-dependent.
Super Low Density Polyurethane Systems for Sports Shoes
Authors: Sawai Minoru , Miyamoto Kenichi , Takemura Kazunari , Mori Masahiro , Kiuchi Kazuhiko
Published: July 2017

This paper describes in detail a new concept of producing super light weight (0.24-0.26 g/cm3) polyurethane (PU) midsoles to compete with EVA for sports shoes. Materials for the midsole of the dual density sport shoes are composed of PU or EVA. Though PU midsole has good cushioning (resilience), adhesive and processing properties compared with conventional EVA systems, it is difficult to reduce the molding foam density drastically. Recently, developments for high performance PU systems have focused on reducing the density while maintaining high physical properties. To solve this problem, we have developed several new progressive technologies. The first uses a polyesterpolyol with functional cohesive units in the main polymer chains. Using this polyesterpolyol, the hard segments of PU become tougher. The second is distributing the cell diameter gradient toward the center of the foam cross section. The split tear, which is one of the most important physical properties for a midsole, has been improved drastically. These new technologies are the best way to spread super light weight PU to new applications and markets.
New Additive Solutions for Low VOC in HR Molded Foams
Authors: Sikorski Matthias , Wehman Cor , Cordelair Holger
Published: July 2017

There is strong pressure on the suppliers of flexible molded foam for automotive seating to reduce the amount of volatile organic compounds (VOC) in their products.

At the moment the main sources of VOC are the catalysts and silicone surfactants. The most effective means to reduce or even eliminate the VOC originating from the amine catalysts would be the use of amines containing reactive groups such as primary or secondary amine and/or hydroxyl groups. These loose however a lot of their activity when they are built into the foam structure, which hence might lead to insufficient flow and / or curing. A careful balance of chemical reactivities and catalytic activities is therefore needed.

Nitroil(r) Performance Chemicals carried out a study on the performance of a number of such reactive amine catalysts, in combination with other reactive or non-reactive amines. The main focus was of course on VOC, but maintenance of acceptable processing and physical foam properties was another major requirement. A series of combinations were evaluated in a TDI-based standard formulation and compared to a combination of traditionally used non-reactive amine catalysts.

In this presentation, it will be shown that the use of reactive amines led to a considerable reduction of VOC. By using only reactive amines, a VOC reduction of ca. 50% was obtained, and virtually no amine was present in the VOC. Good foam processing was obtained while physical foam properties were not significantly affected, with the exception of HACS. This property suffered from the use of reactive amines. By using PC CATS HPI as the basic catalyst in combination with a non-reactive amine as "blow" catalyst, the values for all physical foam properties, including humid aging compression set (HACS), were quite acceptable, while a VOC reduction of ca. 20% was obtained.
Employment of Zero ODP Blowing Agents for Polyurethane Rigid Foams for Thermal Insulation
Authors: Cecchini C. , Cancellier V. , Cellarosi B.
Published: July 2017

The problem of ozone depletion in the atmosphere is becoming more and more important. Consequently, many countries introduced more restrictive regulations in comparison with the Montreal Protocol and its subsequent revisions, anticipating the phaseout of CFC.

The introduction of HCFCs, whose molecules are less harmful to the ozone, is entering a transitional period awaiting more conclusive solutions (e.g., zeroODP systems). In this respect EniChem has been concentrating its efforts insetting up systems for the production of PU rigid foams blown with HFC-134afor thermal insulation.

Significant progress has been made on the employment of this blowing agent in the refrigeration application. Initial thermal conductivity values at 230°C of about 21 mW/mK in real cabinets were obtained, comparable to that of reduced CFC-11 systems currently used in the market. Energy consumption data were also equivalent to reduced CFC-1l-containing refrigerators.

Further research allowed us to also extend the employment of this blowing agent for production of continuous panels, overcoming the problem of excessive "frothing effect" that until now limited the use of low boiling agents in this field. Good material distribution and mechanical characteristics were obtained, and in particular again a thermal conductivity value at 230°C of 21mW/mK.

The most interesting alternative, from the technological and scientific point of view, however, is the blowing obtained only by CO2, which is produced by there action between water and isocyanate. EniChem/PU Division research in this respect has been basically directed to the reduction of initial and aged X value, without leaving out other important aspects, like dimensional stability and adhesion to facers.

The results of this research allowed the achievement of interesting performances both in the continuous panels and in the refrigeration cabinets production, demonstrating the possibility of strongly reducing initial thermal conductivity down to 22 mW/mK at 230°C. Moreover, use of PU matrixes of lower permeability to CO2, with respect to normally accepted values, limited the aging problem so that after 3 months at room temperature a panel without skin,40 mm thick, increased its thermal conductivity value only 10%.
Blowing Agent Emission Calculations for a Refrigerator
Authors: Shankland I. R.
Published: July 2017

This paper presents an outline of a model which can be used to estimate the concentration of blowing agents emitted from the foam insulation into the cavity of a domestic refrigerator. The basic assumption of the model is that blowing agent is emitted from the foam via a diffusion process and finds its way into the refrigerator cavity via holes and slots (for feed-throughs, shelves, etc.) which are cut in the plastic liner. The concentration of blowing agent inside the refrigerator decays asymptotically with time and depends on the diffusion coefficient and initial concentration of blowing agent in the foam, the number and surface area of holes through the plastic liner, whether or not the foam is adhered to the plastic liner, and the air exchange rate for the refrigerator.

The model calculations indicate that, under normal operating conditions, the blowing agent concentration inside the refrigerator is very low, typically, parts per billion by volume. It is believed that the assumptions on which the model is based are conservative, i.e., the model over-estimates the concentration of blowing agent in the refrigerator. The sensitivity of the calculated concentrations to these assumptions is also discussed.
Effective Diffusion Coefficients of CO2 and HCFC-22 in Polyurethane and Polyisocyanurate Foams
Authors: Bhattacharjee D. , Booth J. R.
Published: July 2017

Thin-slice accelerated desorption of gases using a gravimetric methodology has been used to determine effective diffusion coefficients of both carbon dioxide and HCFC-22 in thermoset foam structures. Foam samples consisting of a polyurethane appliance foam and a polyisocyanurate boardstock foam both blown with CFC-11, and polyurethane foams blown with HCFC-22 and carbondioxide have been employed as polymer substrates for the desorption measurements.

A modification of the sorption equations has been developed to describe the special case of two component simultaneous desorption from a uniformly heterogeneous continuum. One component must desorb significantly faster than the other component to separate the individual weight-loss slopes.

For those foam samples that were manufactured with CFC-11 and the diffusion of the blowing agents is still occurring, the initial slope must be determined. Core slices from each sample, 0.25 cm thick, were allowed to saturate with air. The sample weights were monitored daily for several weeks. The initial blowing agent loss slopes, weight against scaled age, were determined for each slice.

The slices were then saturated with a gas mixture, of 1 atmosphere air and 0.5 atmosphere of the secondary gas, either CO2 or HCFC-22, for one month. After the gas pressure was vented to the ambient atmospheric pressure, the slice weight was monitored until the weight curve for a slice coincided with the continuation of the initial blowing agent slope for that slice. The difference (increase) in the slope of weight loss during the desorption of the recharged blowing agent was used to compute the effective diffusion coefficient for the sample. The average diffusion coefficient of CO2 was found to be approximately one order of magnitude higher than that of HCFC-22 (i.e., 7.0 × 10-8 compared to 6.6 × 10-9 cm2/sec) through a foam co-blown with HCFC-22 and CO2. The ratio of the effective diffusion coefficients of CO2 and HCFC-22 was not, however, constant from one polymer substrate to another.
A Method for Analysing the Gas Phase in Polyurethane Foam
Authors: Svanström M. , Ramnäs O.
Published: July 2017

A method for analyzing the gas phase in polyurethane foam is described. The gas content of the foam sample is released by grinding in a special sampling equipment made from a metal pipe. The grinding is effected by pressing the cylindrical sample towards a rotating edge at the end of the pipe. The gas released during grinding is collected in a glass syringe, permitting the total gas volume to be determined. The syringe is connected to two gas sampling valves of a gas chromatograph. In the chromatograph, the gas is analysed on two different columns. For the qualitative analysis of samples with unknown gases and for the identification of impurities, a gas chromatograph—mass spectrometer system is used. Since the sampling equipment, with the sample inserted, is flushed with an inert gas before grinding, the "true" volume of the sample can be determined and the pressure in the cells can be calculated.
Understanding the Fundamentals of Forced Cooling in the Production of Blowing Agent Free Flexible Slabstock Polyurethane Foams
Authors: McAfee C. D. , Wiltz E. P. , Skorpenske R. G. , Ridgway D. H. , McClusky J. V.
Published: July 2017

A rapidly developing method for blowing agent elimination in the production of flexible slabstock polyurethane foam is the use of forced cooling. This process overcomes many of the common problems related to discoloration and physical property loss in traditional low density water blown foams. Additional benefits of forced cooling include uniformity of certain physical properties throughout the foam bun and the elimination of storage space for bun curing. Understanding the relationship between the development and potential degradation of physical properties versus time in the production of blowing agent free flexible polyurethane foam is critical to the foam producers' successful implementation of these novel technologies. The prospect of quickly cooling internal bun temperatures to quench the reaction and reduce the resulting exotherm can be influenced by several important parameters. These parameters consist of: (a)novel polyol and modifier compositions for improved foam physical properties,(b) a thorough understanding of amine and tin catalysis, with the possibility of utilizing novel amine and tin catalysts, (c) understanding the time versus temperature relationship, and how this information can be used to ones advantage, and (d) understanding the equipment and process specific conditions involved in the cooling process and deciding what final physical properties are feasible and acceptable. Experiments and data pertaining to these important parameters will be presented and discussed with respect to the current scenarios confronting today's flexible slabstock polyurethane foam manufacturers.
Dimension-Dependent Long-Term Aging of Cellular Plastic Insulations
Authors: Fan Youchen , Kokko Erkki
Published: July 2017

The commercially available closed-cell cellular plastic insulations are typically faced by gaseous impermeable metal foil to prevent transfer of gases from inside and from outside of the foam. Thus, the long-term aging properties of the foams will be different from the unfaced situation. In this research, it has been found by experiments and simulations that the long-term thermal conductivity of the faced foam will follow a simple logarithm correlation.

[ILLEGIBLE]

Where AX is the thermal conductivity increase of the foam after some years later (say 25 years); P is the perimeter of the unfaced surfaces of the foam; A is the unfaced surface areas of the foam; αo and α1, are determined constants. In addition, this research will give this correlation with respect to the CFC-11 and n-pentane based cellular plastic insulations (CPI) under different facing conditions.
Carbon Black in Appliance Foam Insulation
Authors: Pisipati J. S. , Ball E. E. , Galligan P. L. , Gluck D. G.
Published: July 2017

Efforts are continually being made to improve the insulation efficiency of appliance foam to reduce dependency on fossil fuels and to meet federally mandated product energy use requirements. These efforts have become even more important due to impending elimination of chlorofluorocarbons (CFCs) as the blowing agent for polyurethane and polyisocyanurate foams. Conversion to hydrochlorofluorocarbons (HCFCs) or hydrofluorocarbons (HFCs) generally leads to decreased insulation value of foams and therefore, decreased overall energy efficiency for the appliances.

The effects of incorporating carbon black to reduce thermal conductivity of HCFC-141b blown appliance foams are discussed. The work was jointly carried out by Miles Inc. and the Center for Applied Engineering. Studies previously conducted at the Center had demonstrated that carbon black is well suited for use in rigid insulating foams, particularly in urethane-modified isocyanurates. The Celotex Corporation has now commercialized this technology in the building insulation market.

Improvements of 6-9% in initial k-factors were observed when carbon black dispersed in polyols or isocyanates was used either in TDI- or PMDI-based appliance systems. The use of carbon black in HCFC-141b blown systems has the potential to produce foams with insulation values equivalent to CFC-11 blown production foams.

The very fine particle size and inert character of commercially available carbon blacks allow loadings up to 12% by weight in foam polymer. Since the dispersions can result in excessively high viscosities, efforts were also directed towards modifying formulations to improve flow characteristics. Various approaches were taken to optimize carbon black loading in reactants as well as to facilitate processing in the foam process equipment.
Performance of MDI Pour-in-Place Automotive Seating Incorporating Recycled Content
Authors: Hicks D. A. , Kirk A. C. , Stapleton R. J.
Published: July 2017

Increasingly, the automotive industry is requiring demonstration that polymers in automotive applications are recyclable.

The techniques for the recovery and recycling of polyurethane foam from MDI Pour-in-Place automotive seating have been demonstrated. This seating technology is uniquely suited to the recovery of foams for physical and chemical recycling.

The pulverization of flexible foam and its physical recycling back into automotive seating is described with estimations of the costs involved and performance of the resulting product. Recent work on the chemical recycling of MDI automotive seating is outlined.
An Image Analysis Method for Cell-Size and Cell-Size Distribution Measurement in Rigid Foams
Authors: Lewis K. M. , Kijak I. , Reuter K. B. , Szabat J. B.
Published: July 2017

The basic morphological unit of a closed cell rigid foam is the gas-filled cavity surrounded by cell walls and struts. Typically, these cavities (cells) are pentagonal dodecahedral or tetrakaidecahedral. Their average dimensions and dispersity are known to influence foam physical properties and foam performance. We have devised a reliable method for the measurement of cell-size and cell-size distribution which exploits both geometry and statistics, and which has allowed the realization of useful correlations and trends in our development of rigid foam formulations and additives.

A thin slice of foam (100-300 microns) is subjected to optical microscopy and image analysis. Measurements of the areas of cell windows and of the average ferets of these windows are made independently. Windows are usually pentagonal, hexagonal or square and are variously distorted. Cells are assumed to be dodecahedral and cell diameter ( d) is calculated by the formulae:

d = 2.1354 (area)1/2

d = 1.7013 (feret)

Thereby, two independent determinations of cell diameter are obtained from each window viewed. Values are typically within 2% of each other. Cell-size distribution is quantified by measuring a large number (~ 500-1000) of windows and calculating the simple and weighted averages.

This paper will present the mathematical basis for the method, illustrate the excellent agreement between the window area and the feret cell-size determinations and demonstrate the utility of cell-size and cell-size distribution data in physical property correlations, for example for k-factor.
The Elimination of Radiative Heat Transfer in Fine Celled PU Rigid Foams
Authors: Eeckhaut G. , Cunningham A.
Published: July 2017

Considerable research in the early 1980s led to the identification of radiative heat transfer as a major contributor to the overall thermal conductivity of PU rigid foam.

Fundamental heat transfer analysis showed that for foam model matrices in which the primary variable was cell-size, an approximately linear relationship was obtained between the radiative heat transfer thermal conductivity contribution λ rad and cell-size. λ rad, was shown to theoretically decrease to below 1 mW/mK when foam cell-sizes were reduced to about 50 μ. This decrease to below 1 mW/mK is considered in this presentation as an effective elimination of the radiative heat transfer mechanism.

With the establishment of a phase-out timetable for R-11, considerable global research activity was focused on the development of fine celled technology capable of exploiting these predictions. In recent years technology for the production of closed cell foams with cell-sizes in the range 100-300 μ have been developed. More recently open celled foams have now been developed for vacuum panel applications with cell-sizes down to the 50 μ level. This series of foams provided a unique opportunity to determine directly the real level of radiative heat transfer that occurs and to therefore determine for the first time the real effectiveness of polyurethane foam matrices to attenuate radiative heat transfer.

The theoretical framework for the investigation adopts what is known as a 3 flux approximation, which allows both absorption and scattering contributions to be taken into account. Spectral I-R directional-hemispherical transmission and reflection measurements were performed using an integrating sphere accessory on a BIORAD FTS-40 spectrometer equipped with a CsI beam splitter. The wavelength region of investigation covered 98% of the black body spectrum.

From the experimental reflection and transmission spectra and the three flux approximation method, the spectral extinction coefficient was determined and then Rosseland averaged. From this Rosseland averaged extinction coefficient, the foam radiative thermal conductivity λ rad at a mean temperature of 283°C was calculated. Using a mean intercept length analysis of an SEM characterization of the foam both parallel and perpendicular to the symmetry axis, it was possible to determine the Z-average cell-size.

Analysis of the results displayed a strong linear relationship of λ rad, with the Z-average foam cell size.

It is shown that for the very fine open celled foams designed for vacuum panel applications, λ rad values below 1 mW/mK could be obtained. This remarkable level of radiative attenuation for PU foam, in combination with the expected thermal conductivity contribution from solid conduction, is shown to strongly support their suitability as potential vacuum insulation matrices.
Research of HCFC Blown Integral Skin Foam[UNKNOWN]mMorphology Study
Authors: Lee L. J. S. , Tsai C. C. , Yuh N. H.
Published: July 2017

HCFCs are well-known to be the most likely liquid candidates which would replace CFC-11 as the blowing agent for polyurethane rigid foam and polyurethane integral skin foam. HCFC-123 (CHCI2CF3) is utilized in this research effort for replacing the conventionally used CFC-11 (CCl3F) in the polyurethane integral skin foam with ozone depletion potential (ODP) level as high as 1.0. CFCs should be phased out prior to 1996.

First, suitable polyurethane integral skin foam is selected from formulation screen bench tests which employ HCFC-123 as the physical blowing agent (optimal chain extender/amine catalyst/organotin catalyst combination). Second, the formulation is scaled up to a pilot plant type line. Additionally, SEM (Scanning Electronic Microscopy) technology is used to study the influence of the factors (i.e. the blowing agent, the overall density, the processing parameters and the position of the product) on intermediate layer morphology.

A morphology model has already been proposed by Shutov (morphology of integral polymer foams[UNKNOWN]mMacromol. Chem., Macromol. Symp. 2, 1986) which concerns itself with the intermediate layer between the skin and the core foam of polyurethane integral skin foam. Polyurethane integral skin foam intermediate layer morphology by SEM technology has not yet been reported in previous literature. Applying SEM technology toward studying the polyurethane integral skin foam intermediate layer is a topic of valuable interest.

The research information contained within could be presented as a reference for the complete replacement of CFCs in the polyurethane integral skin foam which, subsequently, would be aimed toward the final goal of solving global environmental problems caused by the ozone layer depletion from CFCs.
Software to Manage a Continuous Production of Flexible Polyurethane Foams by Slabstock Technology
Authors: Consoli Salvatore
Published: July 2017

Software, for IBM or IBM Compatible, operating in MS DOS environment, has been developed to manage a Continuous Flexible Polyurethane Foam Production. It is subdivided into a Main Menu and into various Sub-Menus that, all together, manage a series of activities, starting from the purchase of all raw materials up to the sale of produced foams. A series of databases, interconnected among them, allows the production of any foam corresponding to the formulations, using either sophisticated machines as Foamax Type or more economical ones. In addition the software allows the calculation of Foam Cost, Raw Materials, and Produced Foam Stocks, while the Raw Materials are purchased and utilized, and the Foams are produced and sold. A Testing and a Print Menu complete its performance.
Video Imaging for Improved Tensile Testing of Flexible Foam
Authors: Robbins S. E. , Rusak M. E.
Published: July 2017

The standard ASTM test method, D-3574 Test E-Tension Test, for flexible polyurethane materials has been automated by integration of a video imaging system, a personal computer, and a laboratory scale robot. The manual cellular polyurethane foam tensile test measurements, stress and ultimate elongation, have been replaced with a sample handling/preparation robot and non-contacting video measurement of sample elongation. This automated application has eliminated a significant amount of the manual labor while accommodating a large sample demand.
A Study of the Reaction Kinetics Involved in a Crosslinked LDPE Foam
Authors: Tai Horng-Jer , Wang J. B.
Published: July 2017

The reaction kinetics of crosslinked low density polyethylene (LDPE) foam systems has been investigated. Dicumyl peroxide (DCP) was used as the crosslinker. The crosslinking reaction of LDPE/DCP system is controlled by a first order decomposition of DCP. The reaction kinetics of a chemical blowing agent, azodicarbon amide (ADCA), and its kicker, zinc oxide (ZnO), was also investigated. The rate of reaction of ADCA is very fast, and a general nth-order reaction kinetics fails to predict its conversion. A model combining a general nth-order reaction kinetics and autocatalytic reaction kinetics was adopted instead. The addition of ZnO into ADCA not only lowered the decomposition temperature, but also accelerated its decomposition. The reaction kinetics of the LDPE/ADCA/ZnO system was also studied, and was found to be similar to those of ADCA/ZnO system. The numerical results in this study serve as a framework for future prediction and simulation of molecular structure changes of a reactive polymeric foam system.
Recycling of Rigid Polyurethane Articles and Reformulation into a Variety of Polyurethane Applications
Authors: White Walter R. , Durocher David T.
Published: July 2017

Recycling of thermoset polymeric materials offers a unique challenge. It is often assumed that thermoset materials in general, and polyurethanes specifically, are not recyclable or only recyclable in limited applications as regrind. Herein, we report the recyclability of polyurethane materials by glycolysis and recovery of a polyol. The glycolysis technology utilized is unique in that the residual free amine content is very low, and the entire reaction mixture is useful as a urethane polyol. This is in contrast to other glycolysis technologies that involve separation steps and ultimately in the production of other more hazardous waste streams. The reaction proceeds at ambient pressure and moderate temperature obviating the need for highly sophisticated control mechanisms. The recyclate properties are relatively insensitive to the waste stream utilized, thus permitting the mixed waste streams as raw materials in the process.

In this investigation, high density non-cellular rigid urethanes have been successfully glycolyzed and formulated into a variety of polyurethane systems. These include applications in energy management technology, as well as other rigid and semi-rigid applications. Inclusion of the recyclate shows little detriment to the physical properties of the resulting polyurethane in a variety of applications.

An example of a closed loop recycling strategy is demonstrated in rigid insulating foam. A cyclopentane blown rigid polyurethane can be glycolyzed and the resulting polyol incorporated into the original system at up to 20% of the polyol component with excellent dimensional stability and thermal conductivity results. Up to 100% replacement shows little sacrifice in physical properties.

Preliminary laboratory results also show excellent potential for both rigid insulation foam and high density, rigid, non-cellular polyurethanes to be amenable to the glycolysis process.

This paper describes aspects of our efforts to meet the challenge posed by an increasing number of our customers to render polyurethanes readily recyclable.
Amide-Modified Polyisocyanurate Foams Having High Thermal Stability
Authors: Zhang Zhongyi , Ashida K.
Published: July 2017

Due to increased fire regulations in the building industry, urethane-modified isocyanurate foams (U-IR foams) have been widely used in place of flame retardant rigid urethane foams. However, commercial U-IR foams still have inherent defects in thermal stability, flammability, friability, and smoke density. This paper discusses a novel method for the preparation of amide-modified isocyanurate foams (A-IR foams) having excellent thermal stability and low friability.

A-IR foams having higher thermal stability and higher flame retardation than those of U-IR foams were prepared using quasi-prepolymers prepared by the reaction of adipic acid with a polymeric MDI at about 70°C in tetrahydrofuran as solvent and at unusual COOH/NCO equivalent ratios of 1/30 to 1/10. After the reaction is completed, tetrahydrofuran was distilled out. In contrast, the one shot process using adipic acid as modifier resulted in inferior foams. As control, U-IR foams were prepared using prepolymers made by the reaction of 1,6-hexanediol with the same polymeric MDI. Both A-IR and U-IR foams were prepared using the prepolymers, HCFC-141b as blowing agent, and the same surfactants and catalysts.

The thermal stability of the amide linkage is higher than that of the urethane linkage, and therefore, the resulting A-IR foams exhibited higher thermal stability than that of U-IR foams. The higher thermal stability of the A-IR foams resulted in higher temperature resistance, lower flammability and less smoke generation. In addition, A-IR foams exhibited lower friability even at high equivalent ratios. On the other hand, U-IR foams having the same NCO/OH equivalent ratios exhibited higher friability.

Detailed studies in the relationship between chemical structure and properties were carried out. These studies included the effect of equivalent ratios on foam properties, e.g., thermal stability, friability, compressive strength, flammability, etc. The effect of catalysts on the reaction profile was also investigated. Comparison of thermal stability by means of TGA and of surface flammability by means of the Butler Chimney flammability test exhibited outstanding improvements in the A-IR foams in comparison with U-IR foams.

In view of these data, it could be concluded that A-IR foams prepared by the quasiprepolymer process at high equivalent ratios exhibited superior properties. Accordingly, amide-modified polyisocyanurate foams could be advantageously used for high-rise building insulation, chemical plant insulation, residential insulation, etc. in place of urethane-modified polyisocyanurate foams.
New Insight into the Chemical and Morphological Differences between Slab and High Resilient Foam Elastomers
Authors: Lidy W. A. , Rightor E. , Thanh H. Phan , Cadolle D.
Published: July 2017

By use of Small Angle X-Ray, Infrared and Rheology methods a wealth of knowledge has been generated in the past about the formation and final morphology of the elastomers which constitute Flexible Polyurethane Foams. The current view is that Slab foam polymers have a three phase structure with polyurea microdomains, macrophase separated polyurea and the soft polyether phase. High Resilient foam polymers do not show the polyurea macrophase and have less of the strongly hydrogen bonded urea visible in IR.

The chain length of the polyurea segments is unknown due to experimental difficulties with isolating these structures from a crosslinked polymer. A new method is being described using monols of the same equivalent weight in place of the triols and separating the species containing the hard segments according to their length by solvent extraction. The chemical composition of the urea segment can then be analyzed by 13C NMR or IR. It was found that a considerable number of short urea chains are present in both Slab and HR foam polymers.
The Effect of Blowing Agent Solubility on the Long Term Dimensional Stability of Rigid Polyurethane Foams
Authors: Singh S. N. , Biesmans G. , Karremans M. , Randall D.
Published: July 2017

More environmentally acceptable blowing agents, such as hydrochlorofluoro-carbons (HCFCs), hydrofluorocarbons (HFCs), hydrocarbons, and carbon dioxide have now replaced chlorofluorocarbon (CFC) blowing agents in many rigid polyurethane (PUR) and polyisocyanurate-modified polyurethane (PIR) foam applications. However, these new blowing agents were not simply "drop-in" replacements for CFCs. In most cases, the structural matrix of the foam had to be adapted in order to accommodate the new blowing agent. Concerns about the long term performance of these new technologies have led to extensive programs of research, not only to address thermal performance, but also to understand the effects of these blowing agent changes on mechanical properties. While a great deal of progress has been made, the polyurethane industry is still in need of a means to fully assess long term mechanical and dimensional stability performance.

One particular problem related to the long term dimensional stability of rigid polyurethane foams is the effect of blowing agent dissolution into the polymer matrix. Such dissolution may cause a softening of the matrix known as a "plasticization effect." In order to reduce the risk of mechanical failure, foam density may be increased, in order to strengthen the foam. However, this raises foam cost, and makes polyurethanes less competitive against other insulation materials. Clearly, the rigid polyurethane foam industry is in need of an accurate means of predicting lowest reasonable density which provides acceptable long term performance.

This paper describes the results of a new test designed to quantify the plasticization effect, which provides a fast and accurate means of assessing long term dimensional stability. The new methodology was successfully applied to a number of PUR and PIR foams, expanded with several blowing agents. The degree of blowing agent uptake into the matrix was quantified, and its effects on mechanical properties of the foam was established. In addition, a few correlations were drawn between the new test and real life long term performance data.

The results indicate that the methodology presented in this paper allows for effective prediction and quantification of possible plasticizing effects associated with any blowing agent in a PUR or PIR matrix.
Vibrational Characterization of Various Polyurethane Foams Employed in Automotive Seating Applications
Authors: Kinkelaar Mark R. , Cavender K. Doug , Crocco Guy
Published: July 2017

As vehicle seat designs have moved from a spring/foam composite design to a foam/pan or deep foam design the vibrational characteristics of the foam has become increasingly important. It is now necessary to understand how to improve the vibrational properties of polyurethane foam to assure a comfortable ride and attenuation at the appropriate frequency ranges. It has been demonstrated via modeling foam vibrational characteristics that one can optimize the vibrational performance of foam by simply comparing foam peak frequency and peak transmissivity—these properties predict the foam transmissivity curve.

Foam technologies included in this work were TDI HR, TDI hot cure and MDI HR systems. Data were presented which explored how vibrational properties correlated to foam IFD and ball rebound. Regression analysis data were also presented which demonstrated how foam formulation and processing variables could change foam vibrational characteristics. Generally, TDI chemistry provided the desired lower natural frequency response and was the least sensitive to processing variables. An understanding of these trends is the first step to assuring a quality ride for deep foam seating.
Indentation Resilience of Conventional and Auxetic Foams
Authors: Chan N. , Evans K. E.
Published: July 2017

Materials with a negative Poisson's ratio (auxetic materials) demonstrate the fascinating property of becoming fatter when stretched. This phenomenon is fundamentally important to the properties of a material and a significant change in the value of the ratio has significant effects on the material's mechanical performance. This article describes foams with a negative Poisson's ratio that show better indentation resilience than conventional foams with a positive Poisson's ratio. The unusual mechanical properties of auxetic foams are attributed to the deformation characteristics of re-entrant (concave polyhedral) cell structures.
Physical Property Measurement and Computer Simulated Performance Prediction of Rigid Polyisocyanurate Foam at Cryogenic Temperatures
Authors: Harris M. S. , Nightingale C. , McDonald P. C. , Keary A.
Published: July 2017

The use of rigid polyisocyanurate (PIR) foam for the insulation of pipework, vessels, equipment, etc., running at cryogenic temperatures has increased slowly over recent years as the advantages of polyisocyanurate (e.g., ease of installation, low thermal conductivity, light weight, etc.) over traditional methods such as cellular glass have become apparent. A major drawback preventing a more rapid acceptance of PIR is that it has not been possible to accurately test key cryogenic properties such as Poisson's ratio and tensile modulus. As a result, accurate modeling of stresses at cryogenic temperatures has not been possible, and some inservice failures have taken place.

This paper presents cryogenic test data on PIR foam, including tensile modulus and Poisson's ratio data which has been measured using a novel technique that allows the precise measurement of these key physical properties. The stresses expected in operation at cryogenic temperatures have been modeled with a view to confirming the technical performance of the PIR foam. The paper focuses on the use of PIR for LNG (liquified natural gas) projects operating at -160°C.

It is believed that this work will give users/specifiers the confidence in the suitability of PIR foams to withstand stresses at cryogenic temperatures. It also gives the foam manufacturer a method of evaluating and optimizing different foam formulations.
Rheological Behavior of Mixtures of Polystyrene with HCFC 142b and HFC 134a
Authors: Gendron Richard , Daigneault Louis E. , Caron Louis Michel
Published: July 2017

The processes for the production of thermoplastic foams, often in the shape of extruded sheets or boards, are largely dictated by the rheology of the mixture of a polymeric matrix with a blowing agent. This paper focuses on the theological behavior of mixtures of polystyrene (PS) and physical blowing agents (HCFC 142b and HFC 134a), examined using a commercial on-line rheometer mounted on an intermeshing co-rotating twin-screw extruder. The PS resin was extruded while the blowing agent was injected at high pressure and various compositions. The extent of plasticization was found to be dependent on the blowing agent concentration and its type. The effects of type of blowing agent, composition, pressure, shear rate and temperature on the theological response were measured. These variables were incorporated into a generalized mathematical model, which described the viscosity of the PS/blowing agent mixture over the studied range.
Acts and Facts
Authors: White Stephen
Published: July 2017

Since the Criminal Procedure (Insanity and Unfitness to Plead) Act 1991 there has had to be a ‘trial of the facts’ to determine whether a defendant found unfit to be tried ‘did the act or made the omission charged against him as the offence’ In Egan (below) the Court of Appeal held that by the ‘act’ was meant all elements of the offence. This holding, while meritorious, plainly violates the intention of the 1991 Act, ignores the history of the phrase ‘act charged as an offence’, and is inconsistent with the meaning that has to be attributed to the phrase when the jury are considering whether to return a special verdict of insanity. It also makes for a further anomaly when a defendant unfit to be tried seeks an acquittal on the ground that he lacked mens rea because of insanity. The proposals of the Law Commission's Criminal Law Team for ‘Counts in an Indictment’ will go some, but not necessarily the whole, way to helping courts identify exactly what is the ‘act charged as the offence’.
Double-Blind Study of Children with Hyperkinetic Syndrome Treated with Multi-Allergen Extract Sublingually
Authors: O'Shea James A. , Porter Seymour F.
Published: July 2017

The purpose of this research was to determine, by double-blind studies, whether the hyperkinetic syndrome is due, in part, to certain foods, food colors, and inhalant allergens and, if so, whether it can be treated by specific immunotherapy sublingually.

The children were tested by the provocative intradermal and sublingual method, and an optimal or neutralizing dose was obtained that was included in a multiallergen extract for sublingual treatment.

The study was conducted over a six-week period-three weeks of treatment with the allergen extract and three weeks with a placebo. Each child's behavior was monitored weekly by parents, teachers, and a psychologist.

Significant improvement was reported in 11 of 14 participants during the three weeks of treatment vs placebo. One child did not complete the study. Possible reasons for failure will be discussed.