**4.1 α-Olefin (co)polymers**

**Poly(1-butene) (PB)** or polybutylene is a specialty polyolefin with niche applications. This stereospecific (isotactic), linear, high molecular weight, low density, and crystalline thermoplastic has extraordinary creep, abrasion, and environmental stress cracking resistance besides superior chemical inertness. According to its unique properties and performance, some of the niche applications of this poly α-olefin include pressurized hot- and cold-water pipes, hot-water blow-molded tanks, plumbing, and heating systems [2]. Moreover, since PB has good compatibility with most of the tackifiers, it is used in hot melt adhesive formulations, especially to increase the sticky "open time" [13]. Also, PB/PE blends are utilized in easy open flexible packaging technology.

Recently, some PB composites with high dielectric constant and break downfield strength besides low dielectric loss are reported, which are susceptible to application in capacitors [14].

**Hydrogenated poly(1-butene) (HPB)** is a safe polyene and can be used as an ingredient in cosmetics [15]. It is used at lower molecular weights (400–1000 Daltons) in lip gloss formulations since such polyene is very shiny and possessing good adhesion to lip surfaces. Other applications of HPB in cosmetics include eye makeup, eyeliner, blushes, and foundation [16].

**Hydrogenated poly(1-decene) (HPD)** is commonly used as a film former in cosmetic formulations. HPDs are available in a wide range of viscosities and are used in skincare, eye shadow, makeup, and lip products due to their non-greasy skin feel [16]. The catalytic oligomerization of 1-decene to tri-, tetra-, and penta-decene chains followed by hydrogenation, results in the production of this polyene. It is available under the tradename of PAO 4–8 by Chevron Philips. Since this polyene is of low acute toxicity and does not raise concern for genotoxicity, it can be used as an ingredient in foods, such as glazing or polishing agent for dried fruits [15, 17]. Other applications of HPD are release coating in bread and loaf pans, lubricant in automatic dough dividers, anti-dusting and anti-foaming agents, and plasticizer in food contact films [18].

Although 4-methyl-1-pentene is one of the comonomers used in linear low-density polyethylene production, **poly(4-methyl-1-pentene) (PMP)** is a commercially available specialty engineering polyolefin under the trade name of TPX™. PMP has extremely low density (0.835 g/ml) and surface energy, excellent heat resistance, and chemical inertness besides high transparency, optical and acoustic properties. The industrial applications of PMP include mandrels and sheaths in high-pressure rubber hose fabrication, release films and papers in synthetic leather production, and LED light mold cups. The extremely low density of PMP makes it as a good candidate for automotive parts due to its lower weight and environmental load. Moreover, it is used in several food-related articles, e.g., baking boxes, food packs and wraps, and microwave-safe dishes [2].

Also, it is suitable for applications where transparency and heat resistance are required, e.g., autoclave medical and laboratory ware, microwave and oven components, and heat resistant wire and cables. Furthermore, since PMP is incompatible with some of the thermoplastics (e.g., poly (ethylene terephthalate)), it is used to create porous PET structures [19].

On the other side, PMP is commercially available as hollow fibers (HFs) used in gas separation membranes, where the gas permeability derived from its molecular microstructure. As it was reported recently, the transport and separation performance of these HFs improved by PMP's crystallinity increment [20].

Ring-opening metathesis polymerization (ROMP) of cyclooctene gives **polyoctenamers** which are marketed under the name of Vestenamer. They are the world's most versatile rubber additive used for years. As a semicrystalline, double bond containing polyolefin additive, trans-polyoctenamers (TORs) act as plasticizers in rubber compounding and processing. The cis/trans ratio of polyoctenamers, which is controlled during the polymerization, determines the degree of crystallinity. Generally, the higher the trans content, the higher the crystallinity and melting point. Also, the extremely high crystallization rate of polyoctenamers is advantageous in the soft compounds cold flow reduction, improving green strength, or reducing shrinkage during calendaring.

Since polyoctenamers take part in the vulcanization process, one may consider them as reactive plasticizers. Also, the high macrocycle content of polyoctenamers reduces their molecular weight significantly. In addition to the low molecular weight, the broad molecular weight distribution of polyoctenamers is responsible for their unusual low viscosity at elevated temperatures. Polyoctenamers enable the compounding of incompatible polymers (e.g., NBR and EPDM), reduce viscosity, heat build-up, mix time and energy intake, improve dimensional stability, quality and filler acceptance, and increase throughput.

Furthermore, polyoctenamers allow efficient processing of waste rubbers into tough materials to be used again, i.e., effective in rubber sustainability [21].

Vistamaxx is the trade name of **propylene-ethylene copolymer (PEC)** produced using metallocene catalysts by ExxonMobil Chemicals, comprised of isotactic propylene blocks with random ethylene distribution where the propylene content is over 70 mol%. This copolymer's chemical structure and properties are intermediate between amorphous ethylene-propylene rubber and semi-crystalline isotactic polypropylene [22]. Considering PEC's good processability and compatibility with a wide range of polyolefins, and very low viscosity, it is used as an ingredient in hot melt adhesives (accounts for up to 70–90% of the mixture providing high-performance HMAs with tunable "open-time") and as a processing aid or viscosity improver in extrusion or injection molding processes to improve the flow characteristics.

Consequently, PEC enhances polyolefin blend properties to deliver improved impact strength, higher flexibility, enhanced esthetics, and lower stress-whitening. Also, it is employed as a sealing layer in co-extruded articles due to its extremely low seal initiation temperature combined with high seal strength. This copolymer is a suitable substituent for wax in masterbatch formulations, optimizing costs by lowering the cycle time. Moreover, the color strength increased in the presence of such copolymer by almost 20% because of its high compatibility with polyethylene and polypropylene and well pigment wetting and dispersion at lower processing temperatures [23–25].

Moreover, using Vistamaxx as a minor component (up to 20 wt%) in spunmelt nonwovens designed for applications such as leg barrier cuffs, diapers and medical gowns results in improved softness [26].

**Olefin copolymer (OCP)** viscosity improvers (VIs) are mainly ethylene-propylene copolymers with ethylene to propylene ratio of 45/55–55/45 synthesized using Ziegler-Natta and metallocene catalysts. Short ethylene sequences in OCPs, are crystallized into fringed micelles while higher-ordered morphologies, i.e., lamellae or spherulites, are absent in such copolymers. Also, the fraction of EE sequences (dyads) and the average length of contiguous ethylene units are raised by increasing the ethylene to propylene ratio. Due to the limited solubility of such OCPs in most mineral oils and consequently the inappropriate function of OCP as VI, the degree of crystallinity should not exceed 25% in OCP VIs [27]. Therefore, the physical properties of OCPs fall in between the characteristics of semicrystalline polyethylene and amorphous ethylene-propylene rubber. This oil-soluble copolymer cold flows at room temperature and improves the low-temperature rheology, thickening efficiency, and bulk handling characteristics of engine oils.

Moreover, some essential functions such as dispersing contaminants, antioxidative stabilization, and antiwearing are combined with the rheology control features on the same molecule by OCPs functionalization. Some hybrids have been commercialized, including dispersant OCPs, dispersant antioxidant OCPs, and ashless antiwear dispersant OCPs. These hybrid lubricants are produced through different methods. The most attractive approaches are free radical grafting of nitrogencontaining monomers such as phenothiazine to provide antioxidant functionality and two-step grafting method. In the second approach, maleic anhydride (or such diacyls) is grafted onto the OCP molecule. Then the amine or alcohol reacts with the anhydride to create imide, amide or ester bonds. Also, many functional OCPs have been described in the patents [28–30].

The future perspective of OCPs includes optimizing viscosity ranges, improving the shear stability of the formulations, and designing novel tailor-made functional OCPs (FOCPs) as low cost, highly efficient, and customer choice multifunctional VIs [27].

**Ethylene-propylene-diene terpolymers (EPDMs)** industrial production returns to the 1960s by ExxonMobil Chemical Company, which was designated as Vistalon™. The development of this terpolymer was a natural evolution of Ziegler-Natta technology after the production of other polyolefins. The saturated backbone of EPDM, compared to other rubbers, and consequently its excellent ozone, environmental, and weather resistance makes it the material of choice in the production of various outdoor articles. Typical applications of EPDM include the automotive industry (weather seals, radiator hose, gaskets, grommets, O-rings, belts), construction industry (single-ply roofing material, geomembranes), electrical devices (wire and cable covers), polymer modification (polymer blends used in automotive bumpers), oil modifiers and so on [31, 32].

Based on developments in Daw Chemicals catalyst technology, novel grades of EPDM, i.e., ultrahigh molecular weight EPDM, known as (UHMW)NORDEL™ were developed. NORDEL is highly efficient in producing thermoplastic vulcanizates (TPVs), light color home appliance gaskets, and black color low hardness molded articles [33, 34].

Recently, the potential future applications of novel paraffin-filled EPDM foams as phase change materials (PCMs) in thermal energy storage (TES) systems have been investigated [35, 36].

#### **4.2 Cyclic olefin (co)polymers**

As a successful example, **ethylene-norbornene copolymers,** well-known as COCs, are synthesized via the copolymerization of ethylene with norbornene (or cyclopentene) using metallocene complexes. COCs are glossy, transparent, rigid and amorphous thermoplastics commercially available by TOPAS Advanced Polymers, Inc. The low shrinkage and high modulus (due to the high norbornene content of about 30–60 mol%) of this copolymer make it available as extruded sheets, casts or blown films, and injection or blow molded finished articles. It is widely used in several applications, including medical devices, packaging films, cosmetics containers, and microfluidics. Moreover, this copolymer's high glass transition temperature (up to 180°C) and high heat distortion temperature (about 170°C) make it appropriate low-cost substituent for polycarbonates (PCs) [2].

Also, the effective thermal radiation shielding of poly (ethylene-*co*-norbornene) based COC foams may open new perspectives in the fabrication of thermal insulation foams [37].

**Hydrogenated polynorbornenes** as cyclic olefin polymers (COPs) were commercialized since 1990's and have found increasing applications in pharmaceutical syringes and vials thanks to their superior properties vs. glass and other transparent thermoplastics. This engineering thermoplastic was synthesized via ROMP of norbornene using Grubb's catalyst and subsequent in situ hydrogenation [38].

Low protein adsorption, outstanding moisture barrier, extremely low extractable, considerable fracture resistance, and transparency make hydrogenated polynorbornene an excellent choice for prefilled syringes and vials suitable for parenteral and lyophilized biopharmaceuticals. Also, the low fluorescence, high optical transmission, low haze, and precise mouldability of such COPs make them great selections for bio-diagnostic and life-science devices. The other advantages of this polymer include low risk of interaction with drug and excellent container closure integrity (CCI) at cryogenic temperatures (polymer/rubber thermal expansion coefficients match). However other candidates suffer from limitations in one or more ways. For instance, despite the extreme resistance of poly (vinylidene chloride) to oxygen and water, its sterilization results in HCl release, which causes compatibility issues.

On the other side, the superior dimensional and optical stability of COPs, even after prolonged exposure to high humidity and heat, are beneficial options for mobile devices and large-format TVs (LCDs and OLEDs). Also, displays with excellent viewing angles can be made from COPs, due to their stable, uniform birefringence even at sharp, oblique viewing angles from any seat [39–42].

Unlike the aforementioned cyclic olefin (co)polymers, Poly dicyclopentadiene (PDCPD) is a thermoset with potential and typical applications in transportation system components such as vehicles' body panels' (cabin roof, floor, engine bonnets, mudguards), agriculture equipments, chemical and wastewater treatment, and renewable energy production (wind turbine blades). PDCPD produced by polymerization of low viscosity dicyclopentadiene using Grubb's catalyst through a ring-opening metathesis approach. It is a successful alternative for metals and ceramics in various durable articles and heavy-duty applications [2].

Recently the degradability and recyclability of thermosets like PDCPD has been investigated. It has been shown that the incorporation of some cleavable bonds within the polymer chains, facilitates the triggered degradation of such thermoset material [43].

**Hydrogenated poly(1,3-cyclopentadiene) (HPCPD)** is synthesized through ROMP of DCPD, followed by the double bond hydrogenation. It is a low molecular weight polymer soluble in volatile and non-volatile hydrocarbons that imparts water-proof characteristics to the formulations and adhesion [16]. HPCPD with low risk of carcinogenicity, toxicity, and allergies is used in several applications, including cosmetics (e.g., film formers, waterproofing agents and blends combinations), creams, lotions, gels, hair, skin and sun care [44–46].

For the first time, **syndiotactic polystyrene (***s***PS)** has been developed in Idemitsu Kosan Central Research Laboratory. It was synthesized using single-site cyclopentadienyl titanium trichloride-based metallocene catalysts in the presence of methyl aluminoxane as cocatalyst [47]. Syndiotactic polystyrene is currently available as XAREC™, which is a superior environmentally friendly engineering thermoplastic. It has a high melting point (270°C) compared to its isotactic analogue (240°C). More importantly, the crystallization rate of *s*PS is 40 to 80 times higher than *i*PS at the same cooling conditions. The high heat distortion temperature, excellent chemical resistance, dielectric constant, and dissipation factor are of the primary advantages of this engineering polymer.

*s*PS is utilized in temperature resistant automotive and home appliance applications and its biaxially oriented film is used in high-temperature resistant films, e.g., ovenable packaging. However, to overcome its inherent brittleness and poor impact

strength, nanocomposites of *s*PS reinforced with glass or carbon fibers, mineral fillers or elastomers are developed [48].

Owe to the excellent thermal, electrical and chemical resistance, low specific density, and being environmentally friendly, *s*PS is prospective in the fabrication of electronic components of hybrid electric vehicles [49].

Styrene-diene (butadiene or isoprene) copolymers are synthesized via anionic polymerization, usually using butyllithium. **Hydrogenated styrene-diene (HSD) copolymers** are used as VI and classified into linear block and star copolymers. HSD block copolymers are synthesized via a step-by-step approach. The blocks synthesized alternatively, i.e., the first block is synthesized and then the second block is added to the "living" polymer. Star-shaped HSDs are also synthesized in two steps. Generally, the core compound is one of divinylbenzene, polyhalogenated hydrocarbons, cyclosiloxanes, or calixarenes. The arms are di- or triblock copolymers of styrene, isoprene, or butadiene, which are grown from the reactive sites on the core [50].

The amorphous nature of HSDs affects the low-temperature flow characteristics. Such di-block copolymers and the associated micelles are efficiently used to improve the oil thickness at higher temperatures (100–150°C). HSDs are mainly utilized in high-performance motor oils for gasoline and diesel engines. Moreover, HSDs will find new applications in top-tier niches thanks to the ease of design of such block copolymers with specific topologies to have specialized features [27].

#### **4.3 Functional polyolefins**

**Alternative olefin-carbon monoxide copolymers** are tough semi-crystalline high-performance thermoplastics synthesized by coordination polymerization using late transition metal catalysts. This copolymer has been commercialized since the late 1990s, and now available as Poketone™ copolymer (ethylene-CO) and terpolymer (ethylene-propylene-CO) produced by Hyosung Chemicals.

Unique engineering properties such as exceptional impact and wear resistance, chemical and fuel resistance, gas barrier properties, and superior ductility over a broad temperature range are the significant advantages of this engineering thermoplastic.

Olefin-CO copolymers possess 2–3 times higher impact strength than poly amide (PA) and polybutylene terephthalate (PBT), higher hydrolysis resistance than PA, and better wear resistance than polyoxymethylene (POM). This thermoplastic is applicable in reinforced thermoplastic pipes (RTP) due to its high gas and hydrocarbon barrier properties. Moreover, its considerable resistance to automotive fluids made it a good candidate for application in the fuel system. Also, since this thermoplastic is safe with low to zero volatile compounds emission, it is used in food contact packaging, toys, and medical devices [51].

Generally, since the microstructural features of olefin-CO copolymers are translated into their macroscopic properties, a detailed understanding of the polymerization mechanism and structure-properties relationships is the key to design and synthesis new olefin-CO copolymers for specific applications. According to the literature, it seems that functional olefin-CO copolymers may find considerable attention in the future. The keto groups in olefin-CO copolymers may act as chemical "hooks" for anchoring the functional groups or crosslinking and curing the olefin-CO article after the processing [52].

The other perspective is incorporating a low amount of in-chain keto groups to render photodegradable polyethylene as an environmentally friendly sustainable thermoplastic while retaining its characteristic properties [53, 54].

**Ethylene-Silicone block copolymers** are novel block polymers in which ethylene and silicone units are covalently bonded together, using an appropriate catalyst system.

In 2018, the Chemical Society of Japan Award for Technical Development was given to Mitsui Chemicals for Exfola™ (first commercial ethylene-Si block copolymer) production and commercialization.

This functional polyolefin is an additive that combines the characteristics of polyolefin and silicone. So, the surface properties of polyolefins (i.e., release properties, water and oil repellency, coefficient of friction, abrasion resistance, and surface smoothness) are affected by such surface modifier, especially in injection molded or extruded articles, sheets, and films. In other words, this functional olefin-based copolymer changes the surface of a molded polyolefin article to silicon-specific characteristics by adding a small amount of this surface modifier during the molding process [55].

Lotryl® MA and Lotryl® BA (SK Chemicals), Optema™ and EnBA (ExxonMobil), and EMAC® and EBAC® (westlake), all are **ethylene-methyl (or butyl) acrylate copolymers (EA)** produced by high-pressure high-temperature radical polymerization, with acrylate content of up to 40 wt%. By increasing the acrylate content, the adhesion, solubility, toughness, compatibility with polar substrates, filler acceptance, and flexibility of the copolymer are enhanced. At the same time, the crystallinity, melting point, softening point, rigidity, and hardness are decreased [56].

Thanks to their outstanding compatibility with other thermoplastics and materials besides superior adhesive properties, EA copolymers are used as impact modifiers in engineering plastics (PET, PBT), base materials for filled compounds (masterbatches, wire and cables), and sealable films and layers in flexible packaging. For example, the application of this copolymer in hot melt adhesive composition, relates to its high compatibility with other polymers and raw materials such as tackifiers, waxes, and plasticizers [57].

Although EA copolymers are widely used in several applications, the harsh radical polymerization conditions (pressure range of 250–3000 bar and temperature range of 150–375°C) lead to a poor control over the microstructure, i.e., broad molecular weight and comonomer composition distributions. Therefore, the synthesis of tailor-made polar copolymers of ethylene under mild conditions, using coordination insertion polymerization and controlled radical polymerization approaches gained much attention in the last years. Well-defined functional polyolefins with controlled architectures and topologies will increase the versatility of such copolymers and opens new horizons in polyolefin niche applications [58, 59].

The introduction of acid side branches into the polyolefin substrate brings unique functionalities to **ethylene-acrylic acid copolymers (EAA)**. The acrylic acid units enhance its adhesion to polar substrates including papers, aluminum foil, metallized films, iron, steel, glass, ionomers and polar polymers (e.g., PA and poly ethylene-*co*-vinyl acetate (EVA)), significantly.

Escor™ an Nucrel™ are commercially available ethylene-acrylic acid copolymers (6–11 wt% AA), produced by ExxonMobil and Dow Chemicals, respectively.

Unlike conventional chemical primers and adhesive solutions, EAA copolymers provide excellent high-speed extrusion coating and lamination without the need to inconvenient and rate-limiting adhesive application and drying. So, EAA copolymers are cost-effective solutions for foil adhesion. Strong bonds form between EAA and the oxide layer on the aluminum that is highly resistant against mild to moderate acidic or basic environments.

Moreover, Nucrel™ AE is a specialized ethylene-methacrylic acid-acrylate terpolymer (EMAA), providing improved foil adhesion and enhanced hot tack strength [60].

*Extending Alkenes' Value Chain to Functionalized Polyolefins DOI: http://dx.doi.org/10.5772/intechopen.99078*

Unistole™ is a liquid thermoplastic, commercially available as **hydroxyl-** or **acid-modified polyolefin**. It is utilized as non-chlorine, colorable, primer, or adhesive compatible with almost all types of paints, used in the automotive industry, medical packaging, printing materials, bonding agents, and tackifiers besides high-performance packaging. It has superior adhesion to a wide variety of polar substrates, such as Nylon 6, polyurethane, PBT, ABS, and EVA, flexibility and heatseal properties.

Surlyn® is a smart intrinsic self-healing thermoplastic based on **partially neutralized** (with Na+ , Mg+ or Zn+ ion) **ethylene-(meth) acrylic acid copolymer** synthesized via high pressure free radical polymerization using tubular reactors by Dow Chemical Company.

This ionomer enables microcrack reparation under specific triggers. Accordingly it is majorly utilized in impact protection applications such as golf balls, boats, or car bumpers [61]. Moreover, its potential application in hypervelocity impactresistant less vulnerable spacecraft protecting bumpers against space debris has been evaluated, recently [62].

In addition, this clear, adjustable, and cost-effective engineering thermoplastic resin is utilized in packaging applications due to its excellent barrier properties and resistance to oil penetration. Also, besides the polar units within the polyolefin chain, the low sealing temperature of this ionomer makes it a good choice for adhesives and tie-layer materials. Moreover, considering the superior puncture, tear, and abrasion resistance of this ionomer, its significant applications include coatings, inks, food packaging, sporting goods, and cosmetics molded containers. The excellent heat sealability and oil and grease resistance provided by EAA ionomers make composite films gain popularity in the food packaging industry and rise in demand for such films.

Since poly (ethylene-*co*-methacrylic acid) metal composites exhibit flexibilities like traditional ionic polymer metal composites (IMPCs), they are considered as promising candidates for novel soft robotic actuators and sensors utilized in finger joints, hip, knee, or segmented limbs as well as energy harvesters [63].

Electrochromic devices (ECDs), such as chromogenic windows in aircraft, automobiles and buildings, are attractive potential applications of electrochromic materials both from the academic and industrial points of view for their selective and controlled visible light and solar energy transmission. Gelatin-based electrolyte films blended with EAA copolymer have demonstrated improved coloration efficiency compared to ones prepared by the solution mixing technique. This solvent-free approach will increase the chance of gelatin-based ECDs early commercialization [64].

**Ethylene-vinyl acetate copolymers (EVA)** are specialty thermoplastics produced via radical polymerization and commercially available with vinyl acetate content of 15 to 45 wt% or even more [65, 66].

EVA is an intelligent choice for flexible, puncture-resistant, and low seal initiation temperature (means faster packaging speeds) food and medical packaging which is a suitable replacement for PVC in non-invasive medical tubing and bag applications. Moreover, thanks to its good flow in the heat seal process and excellent crack resistance, EVA is suitable for block cheese, cereal, snacks, and fresh meat packaging. On the other side, most of the caps, closures and lids are made from EVA due to its good gas permeability, sealability, and heat resistance [60]. Also, EVA is used in automotive seals, for example, rocker head covers, due to its long-term heat stability besides good resistance to automotive fluids [67].

Recently, the low potential induced degradation (PID) and high transparency of new qualified grades of EVA made them promising for encapsulant sheet materials in photovoltaic cells [68].



*Extending Alkenes' Value Chain to Functionalized Polyolefins DOI: http://dx.doi.org/10.5772/intechopen.99078*



**Table 1.** *Function-application review of commercially available specialty polyolefins (SPO).*

## *Extending Alkenes' Value Chain to Functionalized Polyolefins DOI: http://dx.doi.org/10.5772/intechopen.99078*

### **Random terpolymers of ethylene-vinyl acetate-maleic anhydride**

**(EVAMAH)** are manufactured by the high-pressure radical polymerization process. They are commercially available as Orevac® T. A transparent, flexible, soft, and reactive polyolefin-based functional thermoplastic with superior adhesive properties to several polar and non-polar substrates, generally utilized as tie-layer in multilayer films, tubes, and pipes. It is used to bond diverse solid substrates such as PA, PU, and PET films, metallic foils, fiber glass fabrics, textiles, artificial leather, natural fibers, wood, and foams.

While vinyl acetate units provide softness, flexibility, and polarity to this terpolymer, maleic anhydride gives reactivity to Orevac® T, leads to adhesive properties far better than EVA copolymers [69].

**Ketone-Ethylene-Ester (KEE) terpolymers** are commercially available as Elvaloy ™ provided by Dow Chemicals. KEE improves the durability, flexibility and long-lasting characteristics of other resins. In addition, when combined with PET, it provides desired level of low-temperature toughness, especially in refrigerated and frozen meals.

Moreover, KEE terpolymers modify the long-term properties and load carrying capacity of asphalt as polymeric modifiers. Also, the permanent flexibility, high cutting, puncture, shrinkage, and chemical resistance of Evaloy/PVC compounds made them the most durable, fastest to install, and most accessible to repair, highperformance single-ply PVC roofing [60].

A list of the specialty polyolefins which has been reviewed in this chapter, is given in **Table 1**. The trade name, manufacturer, Functionalityality added to the polyolefin chains, and applications of such specialties are summarized.
