Abstract
Over the last 10 years a "new generation" of single ply systems have entered the North American market. Most have touted the benefitt/properties of being EPDM-like with the weldability of plastic membranes. Today, they are generally grouped as a family called thermoplastic polyolefin. This group is a member of the thermoplastic family. Thermoplastics incude a wider variety of sytems such as: poly(vinyl) chloride (PVC), ketone ethylene ester (KEE), thermoplastic elastomers (TPE), thermoplastic polyolefin (TPO), etc. All thermoplastics share some of the same characteristics, e.g., heat wealdability. However, they have very different chemical and physical/ mechanical properties. As part of a five year investigation, mechanical (strength and elongation) and chemical thermogravimetry and dynamic mechanical analasyis methods of evalution are being used in this paper to characterize in-service thermoplastic polyolefin (TPO) roof membranes. It was foudn that the polyester scrim reinforced membranes were superior intensile strength and elongation as compared to those reinforced with random mat of short glass fibres. It was also found that the term TPO could be confusing and very vague because of the multitude of acronyms. Standareds shoud consider differentiating between the different types of TPOs (i.e., polyethylene or polypropylene). Bzsed on thermogravimetry, at least four different formula types of TPOs are currently in service. Also, standards should consider using the glass transition temperature to characterize ageing/weathering of membranes. One of the concerns with TPOs in North America is the field welding of seams. For example, it was reported that cold welds frequently occur; that the start and stop postitions of the robotic welder are especially critical, that there is a narrow welding window between cold welds and scorch/burn through, etc. It was also reported tha t TPOs could be welded at a faster speed than other thermoplastic membranes. As a result, the effects of welding parameters on the seam strength of TPO rooifng membanes were investigated. This paper will report on the above and now it applies to TPOs in North America. It includes a table of physical properties for North American TPOs currently available. Data from recent staic and dynamic wind uplift are alos presented.
Over the last 10 years a "new generation" of single ply systems have entered the North American market. Most have touted the benefitt/properties of being EPDM-like with the weldability of plastic membranes. Today, they are generally grouped as a family called thermoplastic polyolefin. This group is a member of the thermoplastic family. Thermoplastics incude a wider variety of sytems such as: poly(vinyl) chloride (PVC), ketone ethylene ester (KEE), thermoplastic elastomers (TPE), thermoplastic polyolefin (TPO), etc. All thermoplastics share some of the same characteristics, e.g., heat wealdability. However, they have very different chemical and physical/ mechanical properties. As part of a five year investigation, mechanical (strength and elongation) and chemical thermogravimetry and dynamic mechanical analasyis methods of evalution are being used in this paper to characterize in-service thermoplastic polyolefin (TPO) roof membranes. It was foudn that the polyester scrim reinforced membranes were superior intensile strength and elongation as compared to those reinforced with random mat of short glass fibres. It was also found that the term TPO could be confusing and very vague because of the multitude of acronyms. Standareds shoud consider differentiating between the different types of TPOs (i.e., polyethylene or polypropylene). Bzsed on thermogravimetry, at least four different formula types of TPOs are currently in service. Also, standards should consider using the glass transition temperature to characterize ageing/weathering of membranes. One of the concerns with TPOs in North America is the field welding of seams. For example, it was reported that cold welds frequently occur; that the start and stop postitions of the robotic welder are especially critical, that there is a narrow welding window between cold welds and scorch/burn through, etc. It was also reported tha t TPOs could be welded at a faster speed than other thermoplastic membranes. As a result, the effects of welding parameters on the seam strength of TPO rooifng membanes were investigated. This paper will report on the above and now it applies to TPOs in North America. It includes a table of physical properties for North American TPOs currently available. Data from recent staic and dynamic wind uplift are alos presented.
Date
10/2000
10/2000
Author(s)
R Paroli;T Simmons; T Smith; B Baskaran; K Liu; A Delgado
R Paroli;T Simmons; T Smith; B Baskaran; K Liu; A Delgado
Page(s)
173-200
173-200
Keyword(s)
single ply membrane; thermoplastic polyolefin; TPO; polyethylene; polypropylene, FPO; FPA; FPO-A; glass transition temperature; Tg; dynamic mechanical analysis; DMA; thermal analysis; thermogravimetry; wind resistance; static test; dynamic test
single ply membrane; thermoplastic polyolefin; TPO; polyethylene; polypropylene, FPO; FPA; FPO-A; glass transition temperature; Tg; dynamic mechanical analysis; DMA; thermal analysis; thermogravimetry; wind resistance; static test; dynamic test