b'TECHNICAL & RESEARCHmembranes provide high tensile strength, excellenta German chemist working for I.G. Farben in the weather resistance, and ease of installation compared1930s. His work on polymerizing butadiene with to older systems. Their adaptability to variousstyrene resulted in a synthetic rubber that could climates and compatibility with different substratesreplace natural rubber, which was in short supply make them a preferred choice for contractors andduring World War II (Feldman & Barbalata, Synthetic building owners worldwide. Unlike BUR systems, MBPolymers: Technology and Applications, 1996).membranes come in roll form, making transportationThis research laid the foundation for later and installation more efficient. advancements in elastomeric polymers. In the This article explores the history, global adoption,post-war era, Shell Chemical Company built upon modern applications, and sustainability aspects ofthese earlier innovations and developed Styrene-modified bitumen membranes. It also examinesButadiene-Styrene (SBS), a block copolymer their advantages over other roofing systems andthat combined the elasticity of rubber with the their expanding use in waterproofing applicationsprocessability of thermoplastics. Initially intended beyond roofing. Additionally, the economic impactfor use in adhesives and industrial applications, of MB roofing systems, including cost-effectivenessSBS was later adapted for construction materials, and lifecycle benefits, is analyzed to provide aincluding modified bitumen roofing.comprehensive view of their role in the constructionShell researchers pioneered the integration of industry. SBS into bitumen, creating a highly elastic and Origins of Modified Bitumen Roofing durable roofing material. SBS-modified bitumen offered superior flexibility, even at low temperatures, Imper Italia, which began manufacturing APP-modifiedsignificantly reducing the risk of cracking and bitumen membranes in 1967 with its pioneeringextending the lifespan of roofing membranes. By the Paralon product, played a crucial role in the1970s, SBS-modified bitumen membranes had been development of MB membranes. By the early 1970s, these formulations were commercialized and began gaining traction in the European roofing industry. The superior performance of MB membranes compared to traditional BUR systems led to increased adoption. Additionally, as MB membranes were refined, they became more cost-effective, increasing their appeal to a broader market.Two major polymer additives were introduced: Atactic Polypropylene (APP) and Styrene-Butadiene-Styrene (SBS), each providing unique performance benefits. APP-modified bitumen was developed to improve UV resistance and thermal stability, making it primarily suitable for warm climates where elevatedBITEC Phototemperatures could degrade conventional bitumen. SBS-modified bitumen, on the other hand, was designed to enhance elasticity and crack resistance, making it ideal for cold-weather applications where flexibility was crucial. widely adopted across Europe, paving the way for Germany faced a shortage of natural rubbertheir introduction to the North American market.and developed synthetic alternatives, includingDissemination and Global Adoptionstyrene-butadiene rubber (SBR), to meet militaryThe success of modified bitumen roofing systems and industrial demands. The development of SBR,in Europe soon influenced markets in North also known as Buna-S, was led by Dr. Walter Bock, Continued on page 34'