Polyurethane shape memory polymer (SMP) foams are proposed for use as thrombogenic scaffolds to improve the treatment of vascular defects, such as cerebral aneurysms. However, gas blown SMP foams inherently have membranes between pores, which can limit their performance as embolic tissue scaffolds. Reticulation, or the removal of membranes between adjacent foam pores, is advantageous for improv...

Background Cell immobilization is a strategy to enhance the efficiency of biorremediation processes [1]. Polyurethane foams have gained relevance for their resistance to microbial attack and cost effectiveness. Although the phenotypic diversity and lower generation time of bacteria make this group the most studied, yeasts are also able to adhere and grow on inert surfaces. While free yeast cell...

Two field studies were conducted for one year using sorbent-impregnated polyurethane foam (SIP) disks for PCB and PBDE air sampling. SIP disks were introduced by Shoeib et al. (2008) as an alternative passive air sampling medium to the polyurethane foam (PUF) disk and have the advantage of a higher holding capacity for organic chemicals. The first study on SIP disks confirmed their application ...

This work was undertaken to investigate the usefulness of diisocyanate-related protein adducts in blood samples as biomarkers of occupational exposure to toluene diisocyanate (TDI; 2,4- and 2,6-isomers) and 4,4'-methylenediphenyl diisocyanate (MDI). Quantification of adducts as toluene diamines (TDAs) and methylenedianiline (MDA) was performed on perfluoroacylated derivatives by gas chromatogra...

The objective of this study is to investigate an appropriate process to fabricate the wood-polyurethane hybrid composites [wood-polyurethane foam (PUF)]. Rigid PUFs that contain up to 20% wood flours were successfully fabricated from polymeric 4,4-diphenylmethane diisocyanate, polyols, silicone surfactant, dibutin dilaurate/ dimethylethanolamine catalysts, and distilled water (chemical blowing ...

Tannin/furanic rigid foams were modi ed by either polymeric 4,4’ diphenylmethane diisocyanate (pMDI) or a one-component polyurethane still presenting reactive isocyanate groups (PUR). Several di erent sequences of mixing the isocyanate and polyurethane with the chemicals used to prepare tannin-based foams were tested. Scanning electron microscopy (SEM) showed that addition of either pMDI or PUR...

Amit Desai, Maria L. Auad, 1 Hongbin Shen and Steven R. Nutt* Gill Foundation Composites Center, Department of Chemical Engineering and Materials Science, University of Southern California, 3651 Watt Way VHE-602, Los Angeles, CA 90089-0241, USA * E-mail: [email protected] Abstract: Hybrid composite phenolic foams are reinforced with chopped glass and aramid fibers in varied proportions. The mechanic...

In bone tissue reconstruction, the use of engineered constructs created by mesenchymal stem cells (MSCs) that differentiate and proliferate into 3D porous scaffolds is an appealing alternative to clinical therapies. Human placenta represents a possible source of MSCs, as it is readily available without invasive procedures and because of the phenotypic plasticity of many of the cell types isolat...

A self-healing microvascular polymeric foam has been developed to improve the resilience of rigid foam core materials for sandwich structures. We investigated the healing of brittle polyisocyanurate (PIR) foam after mode-I crack separation in a 3-point single edge notch bend (SENB) specimen. A two-part healing chemistry based on a commercially available polyurethane (PUR) foam formulation is em...

BACKGROUND Pressure ulcers (PrUs) are ischemic wounds in the skin and underlying tissues caused by long-standing pressure force over an external bone or cartilaginous surface. PrUs are an important challenge for the overall health system because can prolong patient hospitalization and reduce quality of life. Moreover, 95% of PrUs are avoidable, suggesting they are caused by poor quality care as...