bluuebunny/crossref_metadata_2025 huggingface dataset:
Embeddedness and Contractual Relationships in China's Transitional Economy
Authors: Zhou Xueguang , Zhao Wei , Li Qiang , Cai He
Published: August 2023

Interfirm contracts represent common economic relations in the marketplace; they are also deeply embedded in social relations and social institutions. In the context of China's transitional economy, this study examines how three mechanisms—economizing transaction costs, network-based social relations, and institutional links—affect interfirm contractual relationships in (1) the choice of search channels for contractual partners, (2) the formality and provisions in a contract, and (3) the intensity of social interaction in contract implementation. Empirical evidence is drawn from information collected on 877 contracts from 620 firms in two Chinese cities, Beijing and Guangzhou. The authors find distinct roles of social relations, institutional links, and regulatory environments in the initiation of contractual partners and the forms of contracts adopted, whereas transaction-specific factors play a significant role in the intensity of social interaction in contract implementation. These findings suggest the interplay among economic calculativeness, social networks and institutional links, and the complementarity in the underlying theoretical ideas.
Structural Cohesion and Embeddedness: A Hierarchical Concept of Social Groups
Authors: Moody James , White Douglas R.
Published: August 2023

Although questions about social cohesion lie at the core of our discipline, definitions are often vague and difficult to operationalize. Here, research on social cohesion and social embeddedness is linked by developing a concept of structural cohesion based on network node connectivity. Structural cohesion is defined as the minimum number of actors who, if removed from a group, would disconnect the group. A structural dimension of embeddedness can then be defined through the hierarchical nesting of these cohesive structures. The empirical applicability of nestedness is demonstrated in two dramatically different substantive settings, and additional theoretical implications with reference to a wide array of substantive fields are discussed.
Endoscopic Perichondrium-Cartilage Myringoplasty With Preserving of Anterior Margins and Tuck Grafts for Repairing Anterior Perforation With 3 year Followup
Authors: Liu Yachao , Wei Ruili , Ding Yongqing , Li Yanping , Xin Yunchao , Li Dong
Published: August 2023

Objective:

The objective of this study was to evaluate the graft outcomes of endoscopic perichondrium-cartilage myringoplasty with preserving of anterior margins for repairing anterior perforation with 3 year followup.

Study design:

Prospective case series.

Setting:

Tertiary university hospital.

Materials and Methods:

We performed a prospective study in 47 patients with anterior perforation who underwent perichondrium-cartilage myringoplasty with preserving of anterior margins and tuck grafts. The operation time, graft success rate, hearing outcome, and complications were evaluated at 6 months and 3 years after surgery.

Results:

A total of 47 ears with anterior marginal perforation were included in the study. The perforation size was subtotal in 2 (4.3%) eras, large in 11 (23.4%) ears, medium in 27 (57.4%) ears, and small in 7 (14.9%). The mean operation time was 41.2 ± 5.4 minutes. All patients completed 6 months of follow-up. Residual perforation was observed in 2 patients with medium perforations, the graft success rate was 95.7% (45/47). The mean preoperative and postoperative AC PTAs were 38.1 ± 7.3 dB and 25.4 ± 4.6 dB ( P < .05), while the mean preoperative and postoperative BC PTAs were 9.0 ± 4.6 dB and 9.6 ± 1.9 dB ( P = .672). The functional success was 91.5% (43/47). None of the patients reported sensorineural hearing loss, altered taste, facial nerve palsy, vertigo, or tinnitus during the follow-up period. In addition, 34 (72.3%) patients completed 3 years followup and performed temporal bone CT examination, the mean followup time was 39.1 ± 2.7 months, CT revealed the well pneumatization of mastoids and middle ear.

Conclusions:

Endoscopic perichondrium-cartilage myringoplasty with preserving of anterior margins and tuck grafts is a safe, suitable, and reliable method for repair of anterior perforation with few risk of anterior blunting and lateralization.
Computer-Generated IV/Oral Acetylcysteine for Acetaminophen Overdose Physician Order Form
Authors: Zolnierz Michael , Sesin Paul
Published: August 2023

— N-acetylcysteine (NAC) is commonly used to reduce liver damage due to an overdose of acetaminophen. Until 2003, the nebulized form of NAC, Mucomyst, administered orally was the only FDA-approved treatment for acetaminophen overdose. In 2004, an IV form of NAC, Acetadote was approved by the FDA. The manufacturer of Acetadote has recommended to decrease the total volume administered to pediatric and fluid-restricted patients. Employing the spreadsheet program, Microsoft Excel, a preprinted NAC acetaminophen overdose physician order form is generated. The form displays both an oral and IV NAC acetaminophen overdose regimen. The computer program automatically calculates an appropriate IV NAC concentration for patients weighing 40 kilograms or less. The main purpose of the computer-generated physician order form is to increase medication safety by preventing dosing and administration errors. Institutions can develop physician order forms using the spreadsheet concept.
Ibuprofen Lysine Injection
Authors: Cada Dennis J. , Levien Terri , Baker Danial E.
Published: August 2023

Each month, subscribers to The Formulary Monograph Service receive five to six well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to your Pharmacy and Therapeutics Committee. Subscribers also receive monthly one-page summary monographs on the agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation (DUE) is also provided each month. With a subscription, the monographs are sent to you in print and CD ROM forms and are available online. Monographs can be customized to meet the needs of your facility. Subscribers to the The Formulary Monograph Service also receive access to a pharmacy bulletin board, The Formulary Information Exchange (The F.I.X.). All topics pertinent to clinical and hospital pharmacy are discussed on The F.I.X.

Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. If you would like information about The Formulary Monograph Service or The F.I.X., call The Formulary at 800–322–4349. The October 2006 monograph topics are levetiracetam injection, idursulfase, certolizumab pegol, telbivudine, and etonogestrel implant. The DUE is levetiracetam injection.
Standardized Drug Prescribing Forum
Authors: Pisupati Radhika , Wojcik Janice
Published: August 2023

Patient safety is a complex issue that is constantly evolving. Communication via standardized drug ordering is recognized as one of the key elements to providing a safer hospital stay, as well as a stronger patient outcome. This feature will publish bimonthly and will provide examples of standardized drug prescribing and a forum for discussion.

If you have a template that you believe other hospital pharmacies can benefit from, please submit it along with answers to the questions (seen below in the text) to Joyce Generali, Director of Drug Information at Kansas University Medical Center, 3901 Rainbow Boulevard, Mail Stop 4040, Kansas City, KS 66160 or E-mail at jgeneral@kumc.edu .
Effects of graphene-platelets reinforcement on the free vibration, bending, and buckling of porous functionally-graded metal-ceramic plates
Authors: Hassaine Abdellah , Mahi Amale
Published: August 2023

This paper presents a first investigation of the mechanical behavior of porous functionally-graded material (FGM) plates reinforced with graphene platelets (GPls) nanomaterial. As a main purpose, we extend the research on GPls incorporation from single-component matrix materials to porous metal-ceramic FGMs. Four different through-thickness distributions of GPls and porosities were investigated. The effective elastic modulus of GPls-reinforced FGM was calculated using the Halpin-Tsai homogenization model, and the effect of porosities on elastic properties was considered by an exponential model that is more accurate than the common rule of mixture. A recent hyperbolic higher-order plate theory that satisfies the traction-free boundary conditions and a parabolic variation of shear stresses was used to model kinematics. The influence of various parameters was studied after method validation, and it was revealed that GPls not only can improve the stiffness and mechanical response of FGM plates, but can also eliminate the inherent transverse anisotropy of FGMs and uncouple the static response when dispersed in proper distribution pattern. This effect will result in zero mid-plane extension in bending conditions, in a similar behavior to isotropic plates.
Importance of Maintaining Net Position in Men’s and Women’s Professional Padel
Authors: Escudero-Tena Adrián , Gómez-Ruano Miguel Ángel , Ibáñez Sergio J. , Sánchez-Alcaraz Bernardino J. , Muñoz Diego
Published: August 2023

The objective of this research was to analyze the importance of maintaining the net position in men’s and women’s professional padel. The data sample was drawn from 2,756 padel rallies ( n = 1,434 men’s and n = 1,322 women’s) in matches played during the 2021 season of the World Padel Tour circuit. The results showed that there was no net exchange in 50.7% of the women’s rallies, while in 65.9% of men’s rallies, the servers kept the net. Due to their physical advantages, men servers had more opportunities to finish the rally at the net than women servers, giving them more opportunities to win the rally. However, when either men or women receivers finished the rally at the net, they had more opportunities to win the rally. In addition, both men and women tended to end the rallies with a winner when they were in the net zone and with an error when they were at the back of the court. These findings suggest that wins in padel are closely related to time spent at the net.
Emotional Intelligence Outcomes in Higher Education Institutions: Empirical Evidence From a Western Context
Authors: Soliman Mohammad , Sinha Rupa , Di Virgilio Francesca , Sousa Maria Jose , Figueiredo Ronnie
Published: August 2023

The main outcomes of emotional intelligence (EMI) in the workplace have been researched in a variety of settings, however, few studies have focused on such consequences, particularly in the context of higher education institutions (HEIs). This research is therefore to empirically examine the impact of EMI on work-life balance, job insecurity, knowledge sharing behaviour, and workforce agility at HEIs. A total of 368 responses from academic staff members in Italy were analysed using PLS-SEM. The findings indicated that EMI has a significant impact on workforce agility, work-life balance, job insecurity, and knowledge sharing behaviour. In addition, work-life balance significantly impacted knowledge sharing behaviour, which in turn affected workforce agility. This article adds to the body of knowledge on the human resources management domain by highlighting the key consequences of EMI in HEIs within a western context. It also provides various managerial implications for concerned faculty members and senior managers at HEIs. Research limitations and avenues for further research are given.
Vectorize Me! A Proposed Machine Learning Approach for Segmenting the Multi-optional Tourist
Authors: Egger Roman
Published: August 2023

Contemporary consumer behavior is characterized by its multidimensionality and complexity, which, at the same time, pushes traditional segmentation approaches to their limits. In response, this methodological study proposes a multistage machine learning-based segmentation process using semiotic-semantic community detection. This innovative method was conducted exemplarily and evaluated on a representative sample of 1,101 German travelers. The main contribution of this study lies in the novel use of word vectors, which result from assigning a semiotic meaning to travel-type images. Thus, high-dimensional data could be used during the segmentation process, overcoming several classical segmentation problems. By using semantic similarities, tourists could be grouped and represented in their multidimensionality. From a theoretical perspective, this study was inspired by postmodern tourism practices in order to better understand the (oftentimes) hybrid and multilayered behaviors of tourists. To make this innovative approach reproducible, recommendations for implementation and all necessary data have been provided.
“Mi Familia Quiere Que Regrese”: Retired Latiné Immigrants’ Families’ Expectations to Return to Their Country of Origin
Authors: Kiso Helen , Collazo José Luis , Avila Mayra L.
Published: August 2023

We conducted a quantitative, interdisciplinary study that investigated how financial concerns and varying family connections influence the retirement choices of Latiné immigrants in terms of returning to their country of origin. We hypothesized that being worried about one's finances for retirement, and having strong transnational ties, would lead to familial expectations to return to one's country of origin. Through data collected from a survey through Qualtrics, we found that higher levels of financial worry significantly affected greater familial expectations to return to their country of origin. The transnational ties that influenced the families’ expectations to return to their country of origin was having children, friends, and family not residing in the U.S. Following our findings, we discuss potential future directions and implications relating to transnational ties, remittances, and older Latiné immigrants.
Disability Among Older Immigrants in the United States: Exploring Differences by Region of Origin and Gender
Authors: Burns Shane D. , Baker Elizabeth H. , Sheehan Connor M. , Markides Kyriakos S.
Published: August 2023

Rapid aging in American society will be disproportionately concentrated among the foreign-born. Immigrants in the United States (U.S.) are a heterogeneous population, yet little is known regarding their differences in disability later in life by region of origin. We use data from the National Health Interview Survey on respondents ages 60+ ( n = 313,072) and employ gender-specific logistic models to predict reports of any activity of daily living (ADL) disability. After accounting for socioeconomic factors, compared to their U.S.-born non-Hispanic (NH) White counterparts, the odds of reporting ADL disability were higher among U.S.-born respondents that are Hispanic, NH Black, and NH Multiracial as well as respondents with Mexican, Puerto Rican, Cuban, Russian/former Soviet, Middle Eastern, East Asian, and South Asian origins. Also, Dominican, African, and Southeast Asian women—and European men—reported high odds of ADL disability. Our results highlight heterogeneity in the disability profiles of foreign-born older adults in the U.S..
Validity practices in qualitative research in school psychology
Authors: Sabnis Sujay V. , Wolgemuth Jennifer R.
Published: August 2023

Validity refers to the extent to which a given study reflects the dominant values of a research community regarding what constitutes “good” research. Methodological texts on qualitative research provide a wide range of criteria and strategies to help qualitative researchers validate their studies. Given the importance of these strategies to establish a study as trustworthy and legitimate, the objective of this study was to understand the strategies commonly used by school psychology researchers in qualitative research. We therefore reviewed qualitative research articles published in seven school psychology journals between 2006 and 2021. We found 15 strategies authors used to enhance the validity of their research. We also found that a strategy could be enacted in many different ways by different researchers depending on the context. We conclude by recommending four ways in which qualitative researchers in school psychology can improve their validation practices.
Investigation of methane adsorption in kaolinite–methanol intercalation complex interlayer by Monte Carlo simulations
Authors: Zhu Lei , Song Wei , Liu Chengyong , Gu Wenzhe , Zhao Mengye , Liu Zhicheng , Wang Yang , Hao Riwa , Cheng Hongfei
Published: August 2023

The methane adsorption at room temperature in the interlayer of the kaolinite–methanol complex (Kln–Me) with different methanol content is investigated with grand canonical Monte Carlo (GCMC) simulation. The mechanism and structure of methanol intercalated kaolinite (Kln) is proposed, and the effect of methanol on methane adsorption by Kln–Me is discussed. The results indicate that the methanol adsorption in the Kln interlayer is mostly physical with non-bonded energy. The interlayer spacing ( d) of Kln–Me optimized by the DREIDING force field is in good agreement with the experimental data measured with X-ray diffraction. The configuration, adsorption properties, and adsorption isotherms are obtained for eight Kln–Me systems with different number (2–20) of methanol molecules in interlayer space. By comparing methane adsorption in the Kln–Me interlayer with different number of methanol molecules, we discover the complex interplay of factors influencing methane adsorption in the Kln–Me interlayer, especially the number of methanol molecules and free volume. It is found that the adsorption capacity of Kln can be enhanced by inserting methanol molecules into its interlayer. This analysis also underscores the GCMC simulation as a viable tool to calculate kaolinite/organic intercalation composites for potential applications.
All Creatures Great and Small: A Review and Typology of Employee-Animal Interactions
Authors: Quan Shawn Xiaoshi , Lam Carisa , Schabram Kira , Yam Kai Chi
Published: August 2023

Employees interact with animals in a myriad of ways in the context of work. Herein, we seek to catalog this multiplex phenomenon in order to gain theoretical insights. Our article unfolds in four parts. First, we conduct an interdisciplinary review from which we develop a typology of four employee-animal interactions: working for, with, around, and on animals. Second, we outline the current research for each discrete category. Third, we consider key divergent experiences (e.g., the uniquely gendered nature of each) and convergent themes (e.g., all animal work is emotional and hierarchical) across the typology. Fourth, we supplement our review with two metasyntheses of other workplace team interactions—employee-employee and employee-machine/artificial intelligence interactions—to highlight how the study of human-animal interactions can address current conundrums in the organizational domain. We do so to demonstrate that considerations of employee-animal interactions can offer theoretical value to scholars, including those who may not have an inherent interest in the phenomenon. We complement theoretical extensions with suggestions for future research on core management topics, including humanizing workplaces, the future of work, and team collaboration.
An Inquiry into the Modes of Existence of Latour
Authors: Kelty Christopher M.
Published: August 2023

I offer a story of a memorable encounter with Bruno Latour when he visited Houston, TX, in 2007. I take this opportunity to reflect on the central role that relativism played in his thinking and writing, and how it related to my own experience in science studies. The reflection also raises the question of how relativism might still be a problem that haunts Latour’s more recent work on composing common worlds in the wake of climate change.
Environmental Aspects of Isocyanates in Water and Soil
Authors: Brochhagen F.K. , Grieveson B.M.
Published: August 2023

Liquid TDI and most types of MDI which are liquid at room temperature if spilt in large amounts into stagnant or running water will become solid if the temperature of the water is below 10°C. The reaction of the liquid or solid products with water is relatively slow because the products are practically immiscible with water. The reaction products are solid, insoluble and biologically inert polyureas.

In order to investigate the fate of these polyureas contaminating soil after isocyanate spillages the influence of several types of soil was studied using radio-labelled materials. There was neither an indication of degradation observed nor radioactivity found in soil extracts.

TDI and MDI were of low acute or chronic toxicity to a variety of aquatic species in systems designed to simulate the environment in marine and river water. It has also been shown that these products were of negligible toxicity to growing bacterial cultures. This series of experiments has confirmed that effects of isocyanates on aquatic systems on longer term exposure are unlikely to persist and that aquatic systems should recover rapidly from accidental spillages of TDI and MDI.
Fibre Reinforcement of Reaction Injection Moulded (RIM) Polyurethane Elastomers
Authors: Brenner M. , Gibson A.G. , Shortall J.B.
Published: August 2023

The effect of glass fibre addition, in the form of hammer milled or chopped strand fibres, on the mechanical properties of a commercial RIM polyurethane elastomer has been studied with particular emphasis on creep at elevated temperatures. The resultant reinforced reaction injection moulded (RRIM) composites are seen to have a broad fibre length distribution as well as a fibre orientation distribution. A statistical analysis of these two distributions is used in conjunction with the Cox-Krenchel model to enable composite performance to be predicted. A simple technique for predicting the creep behaviour of short fibre composites, first proposed by Darlington, 1 is applied to RRIM and is seen to be useful for such systems.
Phenolic Foams in the USSR
Authors: Shutov F.A.
Published: August 2023

A review of the technology and properties of the main grades of phenolic foams produced in the USSR is presented. The history and current and future positions of these materials are outlined, as well as recent developments in the industrial products.
The Mechanical Anisotropy of Low-density Cellular Plastics
Authors: Cunningham A.
Published: August 2023

Foam chemicals are processed in a wide variety of physical and chemical conditions. Nevertheless, it is essential to achieve a correct balance between the mechanical properties of the foam. An important factor in the load-bearing capacity of a foam is its degree of mechanical anisotropy. This paper describes a method which attempts to quantify the modulus anisotropy of low-density cellular plastics.
Vertifoam — Continuous Vertical Block Foam Process
Authors: Griffiths A.C.M. , Shreeve P.
Published: August 2023

Over the last 20 years there have been considerable developments of machinery for polyurethane block foam production, from the very early machines which produced low-height blocks with rounded tops, to the latest flat-top machines producing more economical blocks. For various reasons, which will be discussed later, this development of large-block continuous foam machines has required that the machines be of such high output that they are totally uneconomical for the small- or medium-sized manufacturer. Even for the larger producer this high output restricts production of some low-demand grades.

The need for a lower output has, so far, been met by the single-block moulding machine. This is able to make blocks in the smaller production quantities required but sacrifices both quality and efficiency of operation.

The Vertifoam process is able to achieve the versatility of the single-block machine and at the same time compete in terms of quality and block size with the best of the existing continuous slabstock machines. (Patents covering the Vertifoam process are held by Hyman International Ltd.)
Five Decades of Foam Plastics – A Personal Narrative
Authors: Baumann Heinz
Published: August 2023

On the occasion of the 12th International Foamed Plastics Symposium ‘50 Years of Foamed Plastics’, held in Dusseldorf, on 25–26 May, 1983, Professor Heinz Baumann presented a personal narrative which contained many points of historical interest.

The following extracts from his talk illustrate some of the problems met by various researchers in the early stages of developing products in the Cellular Polymer field.

Professor Baumann's own contribution to the development and establishing of UF foams in many applications is well known. His views on the necessity to examine dispassionately the industrial experience in the use of UF foams over many years should be studied carefully.
Foams based on Phenolic and Urea-Formaldehyde Resins Mixtures and their Applications for Heat Insulation of Pipelines. 1. Review: Use of Phenolic Foams as Heat Insulation Materials in Pipelines
Authors: Shutov F. A. , Ivanov V. V.
Published: August 2023

A short review on phenolic foams produced in the USSR is presented, as well as the advantages and disadvantages of these materials for pipe insulation. The main requirements for heat insulation materials for channelless heat lines are formulated. The data on model test experiments under conditions imitating the service of heat insulated pipes are discussed. A comparison of phenolic foams and foamed concrete insulations is presented. On the basis of above mentioned data the aim to create a new type of phenol-resin-based foam is presented.
Foams based on Phenolic and Urea-Formaldehyde Resins Mixtures and their Applications for Heat Insulation of Pipelines. 2. Development of the Process for Producing Grade FL-3 Phenolic Foam and Method of its Application to Pipes
Authors: Shutov F. A. , Ivanov V. V.
Published: August 2023

A detailed description of the preparation of a casting type foam based on phenolic and urea-formaldehyde resin mixtures is presented. The option of an optimal content of urea-formaldehyde resin as well as optimal processing parameters are outlined. Foam with maximum apparent density and minimum shrinkage is formulated. Pouring technique and the process of application of foam insulation to metal pipes are described. Practical recommendations for the production of foam insulation are given.
Cellular Polymers
Authors: Buist J.M.
Published: August 2023

This paper reviews the history of the development of synthetic products to match the properties of natural products and draws attention to the many solid polymers that had been discovered and left on the shelf for 50–100 years. Products made from cellular polymers began to appear in the period 1920–45. Many have succeeded in replacing natural products such as horn, shellac and natural rubber; many have also begun to be chosen by certain industries not only as materials with attractive properties in their own right but because the methods of processing and production are efficient. The main thermoplastic, thermosetting and elastomer polymers and their cellular offspring are discussed and the markets for them in Western Europe are reviewed. All polymers present problems in a fire situation; nevertheless the world would find it difficult to do without cellular polymers and the progress made in improving the performance of certain cellular polymers in fires is encouraging.
Legislation – Standards – Polymers
Authors: Christian S.D.
Published: August 2023

Many measures have to be adopted to ensure the safety of occupants from unwanted fires in buildings. This paper examines the work of fire prevention officers in local authority fire brigades to mitigate these problems by their use of the provisions of the Fire Precautions Act 1971. The implications of the proposals to amend the 1971 Act and the commitment of the Government to use appropriate standards for regulatory purposes are discussed
Mechanical Frothing Process Develops New Applications for Polyurethanes
Authors: Berthevas Paul
Published: August 2023

Mechanical frothing of polyurethane involves beating an inert gas, e.g. air, into a mixture of polyols and isocyanates to produce a stable but still liquid froth with very fine cells which can be knife coated on a substrate at gauges from a few tenths of a millimetre to over 10 mm and is then cured by application of heat to produce a microcellular urethane elastomer.

This process and the resulting urethane foams find applications in the back coating of floor coverings, e.g. carpets, artificial grass, vinyl floorings, sports surfaces as well as for the production of shoe inner soles, tapes and gaskets where their properties compare favourably with those of the alternative backings of rubber or PVC foams used until now.
Fire, Foams and Furniture
Authors: Paul K.T.
Published: August 2023

Placing the words Fire, Foams and Furniture together, may create a picture of rapidly burning high temperature fires with dense smoke. This is almost the traditional view of furniture containing polyurethane foams and while it is recognised that such furniture does exist, it must be emphasised that many items of furniture containing polyurethane foam have excellent fire behaviour.

Foams used in furniture can be the flexible polyether foams used for upholstery but the latter could also comprise other materials, e.g. polyester fibre mats, waddings, rubber latex foam, etc. Foams may also be found as flexible fire barrier materials and also as rigid structural elements.

The outer layer of upholstered furniture is almost invariably a fabric. Many fabrics exist; in conjunction with the sub-structure of the upholstery they determine the ignitability and initial burning characteristics of the furniture. By carefully selecting materials and considering the interactions of materials and design, it is possible to build furniture which will resist large ignition sources even when vandalised Such performance demands inevitably lead to compromises and limitations to the choice of fabrics or designs and to the comfort (e.g. soft or hard) of the furniture. They may also probably lead to increase in costs. Modern technology has produced materials which will, in selected designs, give extremely good fire behaviour. It is the responsibility of the specifiers and purchasers to decide the level of performance required in a particular end-use environment and thereby create a market for such products.
PVC Foams: Their Use and Fire Behaviour
Authors: Hitch M. J. , Rolph D. C.
Published: August 2023

Additives used in conjunction with PVC, in particular plasticisers, allow the compounded polymer to have properties ranging from a rigid load-bearing material to a soft flexible substance suitable as a replacement for leather. PVC foams are used in applications as diverse as building cladding, ‘leather-like’ upholstery, decorative wallcovering, cushion flooring and upholstery filling. PVC itself is ‘self-extinguishing’ and does not spread flame, but some of the additives used to impart flexibility can cause the PVC to lose this characteristic, although still retaining its non-drip and no-afterglow behaviour. However, careful formulation, either using a non-flammable plasticiser or by adding a flame retardant, does permit the high fire resistance of PVC foams to be preserved. The way in which the fire performance, as well as the physical properties, of PVC foams can be tailored is discussed here in some detail. The test results for a number of commercially available PVC foams are given and compared with the specified performance of the particular end products.
Fire and Foams in Transport Applications — Aircraft
Authors: Virr L.
Published: August 2023

This paper deals with the application of foams within aircraft cabins, the associated resistance to fire standards contained in air-worthiness requirements and their relationship to the various potential fire risks. The results of international research into the improvement of these fire standards, with particular emphasis on the use of polyurethane foams within aircraft seat cushions is discussed. The results of CAA sponsored research undertaken by the Fire Research Station using different material combinations and different ignition sources are illustrated.
The Performance of Flame Retardants in Rigid Polyurethane Foam Formulations
Authors: Buszard D.L. , Dellar R.J.
Published: August 2023

The flame retardant properties of rigid polyurethane foam compositions are determined by the type and level of flame retardant, the isocyanate index of the foam and the structure of the polyol.

Three phosphorus-based flame retardant additives are compared using the BS 4735 horizontal burn test and the DIN 4102–B2 vertical burn test in a wide range of polyol types. The results obtained are consistent with the phosphorus content of the additives. Dimethyl methylphosphonate with a phosphorus content of 25% proves to be the most effective flame retardant. Surprisingly, the chlorine content, which accounts for nearly a third of the trismonochloropropyl phosphate molecule, does not appear to exhibit any flame retardant effect above its phosporus content. Reoflam 306, a proprietary halogen-free additive with a phosphorus content of 15·2%, enables polyurethane foams of normal index to be formulated to meet the requirements of DIN 4102–B2 without the addition of a flame retardant polyol

Both test methods clearly showed that the aromatic-based polyols have inherently better flame retardant properties than the aliphatic-based polyether polyols.
Study on Isocyanurate-Modified MDI. 2 — Application for Preparing Rigid Polyisocyanate Foam
Authors: Imai Yoshio , Hidai Takao , Inukai Takao , Nakanishi Takehisa
Published: August 2023

Some properties of low density rigid polyisocyanurate foam obtained by using isocyanurate-modified polymeric MDI have been investigated and compared with controls using unmodified isocyanate. Friability of foam has been greatly reduced, and foam-cell size has become smaller. The compression strength and dimensional stability of the new foams described have also been improved; especially noteworthy is the excellent dimensional stability which has been obtained at temperatures above 150°C.
The Use of Chromium Modified Azodicarbonamide as Blowing Agent for Polymer Compound Foaming
Authors: Šimoníková Jarmila , Svoboda Jiří , Šimoník Josef
Published: August 2023

The activation of decomposition of azodicarbonamide by chromium has been studied. The aim of the experimental investigation was the development of a method providing azodicarbonamide modified by chromium during its production. It has been shown that modified azodicarbonamide, containing residual chromium from its preparation does not need to be activated when used as a blowing agent in the production of foamed polymeric materials.
Rigid Polyurethane Foam: What Makes it the Most Effective Insulant?
Authors: Cunningham A. , Sparrow D. J.
Published: August 2023

The fundamental mechanisms of heat transfer through rigid polyurethane foam (PUR) are discussed in terms of three distinct elements λg, λs and λr, where they represent heat transfer by thermal conductivity through the gas phase, solid phase and by radiation, respectively.

Estimated values for λg and λs are given and, from the known λ -value of the PUR foam, λr is estimated by difference. However, there are indications that factors other than cell size affect the value of λr, giving scope — within the existing foam technology — to reduce the λ -value by a reduction in λr to its theoretical minimum.

Using a novel polyol system in combination with high functionality isocyanates, the initial foam λ -value has been reduced by about 13% from its current level. Further optimisation to give foam with maximum insulation efficiency is in progress.
Determination of Average Molecular Mass of Polyols by Freezing Point Depression: Method to Avoid Interference by Water
Authors: Huszár Klára Parlagh , Pásztor Mária
Published: August 2023

The determination of MM of polyols by gel permeation chromatography is not always applicable, especially for the range 500–1500. The paper outlines a method using freezing point depression in acetophenone and since both this solvent and most polyols are hygroscopic, the interference by residual and entrained moisture is overcome by the use of a 4A type molecular sieve.
Removal of TDI and Recovery of CFC: Practical Experience with an Activated Carbon Filter System Installed at a Soft Foam Producer
Authors: Sporon-Fiedler Axel
Published: August 2023

Over the last few years Fläkt Danmark A/S and associates have conducted extensive investigations on CFC-recovery and TDI-removal by absorption on AC (activated carbon) in soft foam production. The research has consisted of measurements at existing foaming lines, pilot plant tests on site and one semi-industrial application.

The research so far has yielded valuable information on several issues to be considered when designing full-scale CFC-recovery installations; for example:

Proper and cost-effective plant design, including the air extraction system and the AC-recovery system itself

Quality and quantity of the recovered product.

Carbon lifetime to be expected and TDI adsorption mechanism.

The information gathered so far forms a good basis for the design of full-scale CFC-recovery systems that will keep emissions of TDI and CFC well below the limits demanded by the environmental authorities, at a reasonable price. This paper gives a description of the research carried out so far and a few examples are included to illustrate the economic aspects of CFC-recovery.
Insulation and the Thermal Performance of Buildings
Authors: Burberry Peter
Published: August 2023

This paper describes the way in which buildings exercise a major controlling influence over their internal environment and demonstrates by a series of historic and modern examples the degree to which comfort can be improved or energy conservation achieved. It describes the changes in the requirements for insulation in the Building Regulations and the problems which must be overcome in highly insulated buildings. It demonstrates that the steady state U-value concept of thermal performance of walls and roofs is inadequate to predict real thermal performance and shows the savings which can be achieved by high levels of properly designed insulation.
Polyblox Insulation of Concrete Masonry Blocks
Authors: Blackwell J. B. , Blackwell S. W.
Published: August 2023

Energy savings are necessary in both the home and workplace and methods of insulating buildings to maintain suitable temperatures vary, but concrete masonry blocks are commonly used.

The various types of insulation systems for concrete masonry blocks are examined by studying the purpose of insulation, the methods of this insulation and comparing economic results of various systems. A new patented system where a rigid polyurethane foam is cast on the full face of the concrete block, avoiding thermal bridges, is described.

Existing methods of insulating concrete blocks are reviewed and some disadvantages are identified. The new system has several major advantages which are discussed and the claims made are supported by independent data obtained from Salford University, Warrington Fire Research Centre and Belfast University. Applications for the new system in offices and housing schemes, both private and government, are described.
The Relative Thermal Stability of Polyurethane Elastomers: 2. Influence of Polyol-diisocyanate Molar Block Ratios with a Single and Mixed Diisocyanate System
Authors: Barikani M. , Hepburn C.
Published: August 2023

Castable polyester polyurethane elastomers (PU's) based on the system polycaprolactone diol (Capa 225)/trans 1, 4–cyclohexane diisocyanate (CHDI)/1,4 butane diol (1,4–BD) were synthesised to study the effect of various polyol-diisocyanate block ratios on thermal stability. The influence of mixed diisocyanates on thermal stability was also investigated by using CHDI as co-diisocyanates in both Capa 225/H12MDI/1, 4–BD and Capa 225/TDI/1,4–BD based PU elastomers. Experimental techniques utilised to assess thermal stability were Dynamic Mechanical Thermal Analysis (DMTA) and Differential Scanning Calorimetry (DSC). Improved thermal stability was observed in both the higher block ratio PU's and in the mixed diisocyanate systems (H12MDI or TDI with CHDI). The temperature resistance was found to increase about 20°C when the block ratio changed from 1/2/1 to 1/3/2 in comparative systems. Hard segment transition temperatures were also found to increase as the block ratio increased. It was also found that changing from the mixed H12MDI+CHDI based PU to a TDI+CHDI system increased thermal stability by 25°C.
The Expanding World of PTFE
Authors: Norman E.G.
Published: August 2023

No development in the history of fluorocarbon polymers has been more remarkable than that of the microcellular expansion of PTFE without the use of blowing agents. This article summarises the development of the GORE-TEX TM process by W.L. Gore & Associates, Inc.

PTFE (polytetrafluoroethylene) has been referred to as both the ‘ultimate’ and the ‘eccentric’ thermoplastic. Its extraordinary properties are now well known to polymer technologists. I.C.I, plc has manufactured it under the name of Fluon * for more than 30 years, as have DuPont under their brand name Teflon ** .

It possesses outstanding chemical inertness, excellent electrical and thermal insulation properties, a wide operating temperature range and exceptional non-stick and low friction characteristics.

Apart from its important role in engineering and electrical applications as a solid, full density polymer, the most dramatic impact on its commercial development came with the discovery of the GORE-TEX matrix expansion process. This process, developed by W.L. Gore & Associates, is not dependent on the use of ‘blowing agents’. The microcellular structure is achieved by mechanical stretching under specific conditions; in this way there is no adulteration of the PTFE purity.
The Surface Coating of Polyurethane Substrates, Part 2: A Theoretical Approach to the Interfacial Bonding of Polyurethane Coatings on Polyurethane Substrates
Authors: Heath R.J. , Bidari K.
Published: August 2023

In the first paper of this series a number of manufacturing techniques were reviewed from first hand observations of such practices. Comments were made of the techniques which had evolved on a trial and error basis to optimise the properties of the paint and PU foam substrate composite.

In this paper, the wetting and interfacial bonding phenomena developed in these composites is examined on the basis of currently accepted surface science theories. Wetting and spreading over a surface, followed by interfacial bonding will depend on the initial affinity between the liquid and the solid, although there might be variation from that predicted because of composition changes as the paint system dries. It is suggested for a PU foam/PU surface coating composite, that good adhesive bonding results from a combination of dispersion, polar and covalent bonding interactions. However, because of moulding practice, boundary layers (e.g. release agent residues) and other phenomenon will interfere with the wetting and bonding in some of these systems.

In-mould surface coating has certain advantages over other methods of painting a moulding. In particular the chemical activity of freshly produced surfaces minimises the possibility of boundary layer effects. The spreading pressure, π, which influences surface tension in a system, will be affected by the moulding pressure.

Later papers will report on the examination of various PU/PU combinations, describing the influences and optimisation of the adhesive bond between coating and foam substrate.
Flexible Polyurethane Foam Slabstock Manufacture through the Next Decade
Authors: Webb J.H. , Griffiths A.C.M.
Published: August 2023

The Vertifoam process and machinery was published in Cellular Polymers by A.C.M. Griffiths and P.T. Shreeve in Vol. 3, 1984, 195. In a relatively short period of time the Vertifoam process has proved to be a very commercially successful foam manufacturing process. To date 41 Vertifoam machines have been sold world-wide in 21 countries which include UK, USA, South America, Taiwan, Hong Kong, China, Singapore, South Africa, Zimbabwe, New Zealand, Hungary, EEC, and Middle East. This is a wide geographical spread. In addition to the commercial success further technical progress and development is described in the present review paper which records the past performance of urethane foam block production and looks forward to the future of Vertifoam technology which it is claimed will speed up the curing cycle, purge and collect the chlorofluorocarbon blowing agents, improve and make more uniform the physical properties of the foam throughout the block.
Shock Mitigating Foams, 1. Structure and Property Relationships
Authors: Richardson M.O.W. , Al-Hassani A.H.M.
Published: August 2023

As a precursor to the custom manufacture of shock mitigating foams for helmet liners, assessments are required of the essential structure and property inter-relationships. This paper establishes a rationale for developing such systems in the context of using them for minimising the destructive forces resulting from single heavy impact (crash) and/or repeated light impact (buffeting).

The basic chemistry of polyurethane foam is reviewed, along with physical structure and mechanical property aspects. Methods of predicting impact behaviour from static/dynamic tests are highlighted, including a review of how continuum theory may be applied in practical situations.
Rigid Urethane foamg for LNG Insulation – the Effect of Physical and Chemical Factors on Foam Integrity
Authors: Cervenka A. , Grieveson B.M.
Published: August 2023

Multilayer spraying of rigid polyurethane foam provides an excellent way of insulating storage tanks for liquefied hydrocarbons such as LNG. The viability of such an insulating system depends both on the initial quality of the foam and on its response to the different environments which the foam may encounter during its service life.

As part of a larger programme to develop rigid polyurethane insulation foams for both marine and land storage tanks, several techniques were developed for assessing the quality and performance of the foam. Nitrogen and cyclohexane were used as probes to examine the interfaces between successive layers of foam? it was shown that very careful control of the spray technique is needed. Random deposition of isolated spray droplets outside the main foam laydown pattern leads to substantial porosity of the interface. Each successive layer must be sanded to expose fresh surface which should then be maintained substantially free from adsorbed water until the next foam layer is applied.

A chromatographic technique was developed using the polyurethane foam itself as the chromatographic fixed phase to study the interactions with gaseous environments likely to be encountered in service. These included the stored hydrocarbon liquids, nitrogen, oxygen, carbon dioxide and water (the components of air) and the various compounds which might be present in exhaust gas inerting systems. Hydrocarbons have no effect on the foam. However, there is a strong chemical interaction with oxides of sulphur and nitrogen which have severe deleterious effects on foam properties.
Polyol Recovery from Elastomer Polyurethane Waste
Authors: Simioni F. , Modesti M. , Rienzi S.A.
Published: August 2023

Waste and scraps, from polyurethane elastomers, mainly from the shoe sole production, can be conveniently converted by a transesterification process into polyols which can be reused in the production of rigid foams, with both economical and ecological advantages.

In the transesterification process, secondary reactions leading to amine formation, can be controlled by means of the reaction conditions.

In the production of rigid foam the recovered products are mixed with fresh polyol; the recovered/fresh polyol ratio must be moderate in order to obtain materials with sufficiently high dimensional properties.