responsive polymers as active materials that can be triggered by a change in pH, pressure, temperature, or light to release the active components carried by them. Nanotechnology, a newly fashionable field, has added another dimension to internal (integral) packaging of therapeutics. Products, known as nanomedicines, relying on nanotechnology are now in routine clinical use. These include medicines incorporating polyethylene glycol (e.g., pegfilgrastim), stealth liposomes (e.g., Doxil), polyglutamation (e.g., polyglutamated paclitaxel, Xyotax), and antibodies (e.g., gemtuzumab, Mylotarg). Filgrastim is used to avoid febrile neutropenia in patients undergoing bone marrow transplantation. Attaching polyethylene glycol (PEG) to filgrastim avoids the need for the patient to be injected daily. The product has a linear PEG attached to the N-terminal methionine of granulocyte- colony stimulating factor, so that the bulky PEG component does not interfere with the rest of the molecule or its ability to interact with its cognate receptor. Whereas normal filgrastim is associated with a 48-hour response as it steadily leaks out via the kidneys, this is not the case with pegfilgrastim. Stealth liposomes differ from conventional liposomes in that they are coated with polyethylene glycol which enhances their hydrophilicity and enables them to evade the reticulo-endothilial system, thereby slowing their clearance from the body. Such stealth liposomes containing doxorubicin are used as nanomedicines, Doxil. Once liposomes reach a permeable tissue, such as tumor, they sneak into the interstitial fluid and release their drug cargo. A significantly high concentration of doxorubicin is thus achieved in tumor tissues by administering Doxil instead of free doxorubicin. Stealth liposomes that contain other drugs for cancer treatment are being developed [9]. They include cisplatin, a mitomicin prodrug and a targeted frm of Doxil. A polyglutamated form of paclitaxel (Xyotax) has made it possible to deliver large doses of the drug without the need for extensive premedication and without the risk of alopecia. Another example is anti-tumor antibiotic Calicheamycin, which is licensed in the U.S.A. for the treatment of certain patients with CD33-positive acute myeloid leukamia. Calicheamycin is too toxic for human use on its own, but when linked to a humanized antibody, such as Gemtuzumab (Mylotarg), its toxic effects can be targeted. 7.2.13 Wood–Plastic Composites There is a largely untapped opportunity for wood–plastic composites [10] in packaging and material handling. This is evident from the fact there are nearly 600 million pallets made each year in North America and only about 50 million are plastic. One Canadian manufacturer, Dura-Skid, produces pallets by assembling lineals made from wood-filled HDPE. The main advantage of wood–plastic composites to the pallet manufacturer is the excellent stiffness to weight ratio afforded by wood filler. The greatest opportunity may be in structural foam and twin-sheet thermoformed pallets. 7.3 Polymers in Building and Construction The building and construction industry is being transformed by economic and demographic changes that are creating increased opportunities for plastics products [11–15]. It is next only to the packaging industry in order of importance as a user of plastics, and has proved to be the fastest growing market for plastics use in the last 20 years with increased sales in roofing, flooring, pipe and conduit, windows and doors, plumbing fixtures, and insulators. With its high potential for replacement of nonplastic materials, this market is expected to grow more rapidly. One of the relatively new areas of building applications has been in sports surfaces, which are discussed in a later section at the end of the chapter. The use of nonwood materials in building and construction has been stimulated by the escalating prices of wood construction products. However, a key factor in the growth of plastics in residential construction is consumer acceptance. The advantages of plastics over conventional materials, including improved quality, reduced installation cost, better appearance, durability, and low maintenance requirements, have hastened their acceptance. Poly(vinyl chloride) (PVC) is the predominant plastic material consumed in building and construc- tion; it accounts for almost half of this industry’s total consumption of resins. The largest PVC 7-10 Plastics Technology Handbook q 2006 by Taylor & Francis Group, LLC responsive polymers as active materials that can be triggered by a change in pH, pressure, temperature, or light to release the active components carried by them. Nanotechnology, a newly fashionable field, has added another dimension to internal (integral) packaging of therapeutics. Products, known as nanomedicines, relying on nanotechnology are now in routine clinical use. These include medicines incorporating polyethylene glycol (e.g., pegfilgrastim), stealth liposomes (e.g., Doxil), polyglutamation (e.g., polyglutamated paclitaxel, Xyotax), and antibodies (e.g., gemtuzumab, Mylotarg). Filgrastim is used to avoid febrile neutropenia in patients undergoing bone marrow transplantation. Attaching polyethylene glycol (PEG) to filgrastim avoids the need for the patient to be injected daily. The product has a linear PEG attached to the N-terminal methionine of granulocyte- colony stimulating factor, so that the bulky PEG component does not interfere with the rest of the molecule or its ability to interact with its cognate receptor. Whereas normal filgrastim is associated with a 48-hour response as it steadily leaks out via the kidneys, this is not the case with pegfilgrastim. Stealth liposomes differ from conventional liposomes in that they are coated with polyethylene glycol which enhances their hydrophilicity and enables them to evade the reticulo-endothilial system, thereby slowing their clearance from the body. Such stealth liposomes containing doxorubicin are used as nanomedicines, Doxil. Once liposomes reach a permeable tissue, such as tumor, they sneak into the interstitial fluid and release their drug cargo. A significantly high concentration of doxorubicin is thus achieved in tumor tissues by administering Doxil instead of free doxorubicin. Stealth liposomes that contain other drugs for cancer treatment are being developed [9]. They include cisplatin, a mitomicin prodrug and a targeted frm of Doxil. A polyglutamated form of paclitaxel (Xyotax) has made it possible to deliver large doses of the drug without the need for extensive premedication and without the risk of alopecia. Another example is anti-tumor antibiotic Calicheamycin, which is licensed in the U.S.A. for the treatment of certain patients with CD33-positive acute myeloid leukamia. Calicheamycin is too toxic for human use on its own, but when linked to a humanized antibody, such as Gemtuzumab (Mylotarg), its toxic effects can be targeted. 7.2.13 Wood–Plastic Composites There is a largely untapped opportunity for wood–plastic composites [10] in packaging and material handling. This is evident from the fact there are nearly 600 million pallets made each year in North America and only about 50 million are plastic. One Canadian manufacturer, Dura-Skid, produces pallets by assembling lineals made from wood-filled HDPE. The main advantage of wood–plastic composites to the pallet manufacturer is the excellent stiffness to weight ratio afforded by wood filler. The greatest opportunity may be in structural foam and twin-sheet thermoformed pallets. 7.3 Polymers in Building and Construction The building and construction industry is being transformed by economic and demographic changes that are creating increased opportunities for plastics products [11–15]. It is next only to the packaging industry in order of importance as a user of plastics, and has proved to be the fastest growing market for plastics use in the last 20 years with increased sales in roofing, flooring, pipe and conduit, windows and doors, plumbing fixtures, and insulators. With its high potential for replacement of nonplastic materials, this market is expected to grow more rapidly. One of the relatively new areas of building applications has been in sports surfaces, which are discussed in a later section at the end of the chapter. The use of nonwood materials in building and construction has been stimulated by the escalating prices of wood construction products. However, a key factor in the growth of plastics in residential construction is consumer acceptance. The advantages of plastics over conventional materials, including improved quality, reduced installation cost, better appearance, durability, and low maintenance requirements, have hastened their acceptance. Poly(vinyl chloride) (PVC) is the predominant plastic material consumed in building and construc- tion; it accounts for almost half of this industry’s total consumption of resins. The largest PVC 7-10 Plastics Technology Handbook q 2006 by Taylor & Francis Group, LLC . opportunities for plastics products [11–15]. It is next only to the packaging industry in order of importance as a user of plastics, and has proved to be the fastest growing market for plastics use. for almost half of this industry’s total consumption of resins. The largest PVC 7-10 Plastics Technology Handbook q 2006 by Taylor & Francis Group, LLC responsive polymers as active materials. opportunities for plastics products [11–15]. It is next only to the packaging industry in order of importance as a user of plastics, and has proved to be the fastest growing market for plastics use