Crystalline Characteristics and Their Influence in the Mechanical Performance in Poly(ε-Caprolactone) / High Density Polyethylene Blends.

María L Cerrada,Ernesto Pérez,Enrique Blázquez-Blázquez,Vicente Lorenzo

doi:10.3390/polym11111874

Abstract

Blends of poly(ε-caprolactone) (PCL) and high-density polyethylene (HDPE) have been prepared at different compositions in order to assess the effect of HDPE on gas transport and mechanical behaviors of PCL. Previous to this evaluation, a complete morphological, structural, and thermal characterization were performed using techniques, including SEM, contact angle, FTIR, differential scanning calorimetry, and X-ray diffraction with synchrotron radiation at small and wide angles. Low HDPE incorporations allow interactions to be established at interfaces in the amorphous regions and the enhancement of the mechanical performance. Consequently, the addition of a small amount of HDPE (ranging from 5 to 10 wt%) appears to be appropriate in certain bio-applications where a higher mechanical behavior is required.

Highlights

Poly(ε-caprolactone) (PCL) was first synthesized in the early 1930s by the Carothers group [1], and consists of a linear aliphatic polyester macrochains, exhibiting crystalline characteristics
Blends of poly(ε-caprolactone) (PCL) and high-density polyethylene (HDPE) have been prepared at different compositions in order to assess the effect of HDPE on gas transport and mechanical behaviors of PCL
This fact indicates that polyethylene chains can affect the amorphous or the crystalline PCL phases because some interactions can be established at interfaces. The existence of those local contacts between these two components is deduced from the common region related to the rocking modes from the CH2 groups existing in both macromolecular chains. These results show that the phase segregation, observed from scanning electronic microscopy (SEM) pictures, does not occur in a complete extent and some interactions within the amorphous PCL and HDPE regions take place

Summary

Introduction

Poly(ε-caprolactone) (PCL) was first synthesized in the early 1930s by the Carothers group [1], and consists of a linear aliphatic polyester macrochains, exhibiting crystalline characteristics. During 1970s and 1980s, attention was significantly focused on PCL and its copolymers for their use in drug-delivery devices It was overwhelmed by other resorbable polymers, like polylactides and polyglycolides. PCL has become a highly desirable candidate for applications like the controlled release of contraceptives in matrix implants [9,10,11], since a second surgery for the retrieval of the device could be avoided. Its structural bio-applications can be limited by its relatively low glass transition temperature, Tg (around −60 ◦ C), and its low melting point, Tm (about 60 ◦ C) These are the features that control its mechanical performance (which are deficient under load bearing conditions, requiring considerable mechanical reinforcement) and its barrier characteristics (to oxygen, water vapor and other gases). The use of advanced fabrication technologies, like three-dimensional (3D) printing or electrospinning [12,13], and its blending with other polymers [14,15,16,17,18,19] or fillers [20,21,22,23], can promote the enhancement of those properties

Methods

Results

Conclusion